Who is Shri Lakshman? What is the real Tattva of Sri Lakshman?
Śrī Lakshman Ji Maharaj is enternal brother Śrī Raghunandana. Śrī Lakhan Lal Sarkar appeared in Treta Yuga to participate in the pastimes of Parātpar Par-Brahma Śrī Rāma. Due to Kalp-Bhed many times Śrī Sesh Bhagwān appears as Sri Lakshman but sometimes Śrī Hari Vishnu Himself appears as Śrī Lakṣman at the time when Paratpar Par-Brahmā Śrī Rām, The Lord Of Saket descends. And this was also said by Śrīmad Gangādharāchārya who was 10th Acharya of Śrī Saṁpradāya (Śrī Ramanand Sampraday) in 569 BC in his Śrī Shukaaryamata Deepika & he also quoted a shloka from Brihd Brahma Samhitā;
Śrīmad Gangādharāchārya in Shukaaryamata Deepika:—
साक्षादखिलश्रुत्यर्थसारभूतो हरिः पापहारकः पतितपावनकारकः परब्रह्माख्यः श्रीरामः सुरैर्ब्रह्मेशानादिदेवमुख्यैः प्रार्थितोऽशांशेन अंशश्च अंशसमूहश्चेति अंशांशं तेनेतिव्युत्पतिः कार्या । अत्र प्रथमांशशब्दस्य श्रीवैकुण्ठेशावतारे श्रीभरते शक्तिः। द्वितीयांशशब्देन तु क्रमशः क्षीराब्धीशभूमावतारभूतयोः श्रीलक्ष्मणशत्रुघ्नयोर्ग्रहणम् ।
Meaning is same Śrī Vaikuntha Nath prabhu is Śrī Bharata, Śrī Sheer Shai Bhagwan is Śrī Lakshman & Śrī Bhauma Purusha Bhagwan is Śrī Shatrughana.
For his above statement he has also provided a shloka from Brihd Brahma Samhitā;
वैकुण्ठेशस्तु भरत: क्षीराब्धीशश्च लक्ष्मणः । शत्रुघ्नस्तु स्वयंभूमा रामसेवार्थमागता: ।।
Śrī Bhārat who is lord of Vāikuntha, Śrī Lakshmān who resides in Sheer Sagar (क्षीर सागर) and Śrī Shātrughna who is swayam Bhumā Purushā, all of them incarnated with him to serve Śrī Rāma.
(Narad Panchratra Brihd Brahma Samhitā)
& Infact this shloka has been also used in one of the ancient commentry on Śrīmad Vālmīkī Rāmāyaṇam, Shiromani Tika;
—Valmiki Rāmāyaṇam 1.18.13
Śrī Jīva Gosvāmi quotes the Ayodhyā-māhātmya from Skand Purāņa in his commentary, to say like Śrī Balarāma (being amśī of Sesa ) and Anant-Sesa (Amśa / a part) are two forms, similarly Śrī Lakshman has clearly (shown) two forms - Śrī Lakshman (He, himself being the amśī of Seṣa) and the Anant-Seşa (his part / Amśa) in the Purana.
"It is seen during Śrī Lakshman's final leela in the Ayodhyā-māhātmya (the section of greatness of Ayodhya) from Skand Purāņ—Being forsaken by Śrī Rāma, Śrī Lakshman went to Sarayu and after taking holy-bath, He becomes situated in meditative state, and;
ततः प्रादुरभूत्तत्र सहस्रफणमण्डितः । शेषश्चक्षुःश्रवाः श्रेष्ठः क्षितिं भित्त्वा सहस्रधा ।सुरलोकात्सुरेन्द्रोऽपि समागादमरैः सह ॥
"There, Anant-śesa emerged with his thousand hoods adorned with bright radiant gems. Then the king of Devas, Indra along with all other Devas came there from the heaven".
(Śrī Skand - Purān 18.104.22.168)
ततः शेषात्मतां यातं लक्ष्मणं सत्यसङ्गरम् । उवाच मधुरं शक्रः सर्वस्य च सः पश्यतः ॥
"Then, as all the gods watched, Śrī Lakshman, who is always true to his words, assumed (another ) form of Anant-śesa. With sweet words, Indra offered following prayers to the Lord -"
(Śrī Skand - Purān 22.214.171.124)
इन्द्र उवाच:— लक्ष्मणोत्तिष्ठ शीघ्रं त्वमारोहस्व पदं स्वकम् । देवकार्यं कृतं वीर त्वया रिपुनिसूदन ॥ वैष्णवं परमं स्थानं प्राप्नुहि स्वं सनातनम् । भवन्मूर्तिः समायाता शेषोऽपि बिलसत्फणः ॥
"O' Śrī Lakshman, O Hero, O Destroyer of enemies, You have fulfilled the mission of helping Devas (by destroying their enemies), please return now to your own transcendental abode. O Lord! Your form of Anant-śesa, who has innumerable glittering hoods, has now arrived. Please, return now to Your own eternal Supreme Vaisnava-abode in the spiritual world.
(Śrī Skand-Purān 126.96.36.199-63)
(bhavan-mūrtih Your [especial] form, śesāpi - Anant -Sesa also, samāyātā has arrived now. Now You also, prāpnuhi - please attain (return to), svam - Your own, sanātanam eternal, vaisnavam paramam Supreme Vaisnava, sthānam abode.)
ततश्च इत्युक्त्वा सुरराजेन्द्रो लक्ष्मणं सुरसङ्गतः । शेषं प्रस्थाप्य पाताले भूभारधरणक्षमम् ॥ लक्ष्मणं यानमारोप्य प्रतस्थे दिवमादरात् ॥
"After speaking these words to Lord Lakṣmaṇa, all the celestial-Devas along with their king, Indra respectfully placed him (Lakshman) on the (divine) aerial-car (for his own eternal Supreme Vaishnava-abode), and also respectfully sent the Anant-Seṣa, who can easily carry the great weight of all the worlds, to the Pātāla, and then those celestial-devas went back to the heavenly world."
(Śrī Skand-Purān 188.8.131.52)
—This way Śrī Jeeva-Goswami shows Śrī Lakshman's Amśāvatār (expansion) is Anant Sesa who was also present in the body of Śrī Lakshman during the Avatāra-leela.
In Purānas, It is said 'Śrī Lakshman is Sankarshan, or Sankarshan, the avatār of Sankarshan? - however telling him 'the incarnation of Sankarshan' means the original primeval Sankarshan is the one among the four-fold Vyuha incarnation of Vishnu (Para- Vāsudeva) in Vaikunth. However It is not so because there in Narada Purāņa it is said It is Lakshmana who is Sanakarshan among the four-fold incarnation, Vasu said to Mohini there —
श्रृणु देवि प्रवक्ष्यामि माहात्म्यं लक्ष्मणस्य च । यं दृष्ट्वा मनुजो देवं मुच्यते सर्वपातकैः ॥ चतुर्व्यूहावतारे यो देवः संकर्षणः स्वयम् । सर्वभूमंडलं ह्येतत्सहस्रवदनः स्वराट् ॥
"Oh Devi, Listen! I am telling the greatness of Shri Lakshmana! That God (Lakshmana) is Samkarshan himself in the Chaturvyuhavataar! He alone is the Anant-Shesha, and He is self-illuminated by his own glory (in his Lakshmana form)!"
(Śrī Narad Puran 2.75.2-3)
स्वराट् कहने का अर्थ है श्रीलक्ष्मण अपने निजधाम में अपने प्रभाव से अपने लक्ष्मण रूप में विराजित हैं!
लक्ष्मणस्तु महाभागे स्वयं संकर्षणः शिवः ।
"Śrī Lakshman is actually himself (or original- ) Sankarshan".
(Śrīnārada purāna 2.75.5)
For being the brother and the companionship of Śrī Rāma, Śrī Lakshman dwells with Śrī Rāma in his Supreme transcendental abode, while the Samkarshan, the Vyuha of Vishnu of Vaikunth is told in the second circle. It is also said in the Agama that Śrī Lakshman expands himself in first as Samkarshan, and then Samkarshan expands as Anant Śeşa, thus Samkarshan and Anant-Śeşa are Amśāvatār (Amśa) of Śrī Lakshman, while Sri Lakshman is the original-Samkarshan.
The Tattva of Sri Lakshman Ji Maharaj has been described in Brahma Rāmāyaṇa at the time when he was about to take departure from this materialistic world;
(Gita Press Gorakhpur, Manas Piyush, Balkānd, Doha No.18)
राम नैवोद्धितो वीरो लक्ष्मणो विदधत्स्वकः । रूपन्त्रयं महद्वेषं लोकानां हितकाम्यया ॥ एकेन सरयूमध्ये प्रविवेश कृपानिधिः । सहस्त्रशीर्षा भगवान् शेषरूपी रसाश्रयः ॥ रामानुजश्चतुर्वाहुर्विष्णुस्सर्वगुहाशयः । ऐन्द्रं रथं समारुह्य वैकुण्ठमगमद्विभुः ॥ यानस्थो रघुनन्दनः परपुरीं प्रेम्णागमद् भ्रातृभिर्लोकानां शिरसि स्थितां मणिमय नित्यैकलीलापदाम्। सौमित्रिश्च तदाकलेन प्रथमं रामाज्ञया वर्तते तेनैव क्रमकेन बन्धुमिलितो रामेण साकं गतः ॥
Brahm-Rāmāyaṇa says at the time of disappearance (final-departure to his transcendental abode), Śrī Lakshman assumed two more forms, from one four-armed form of Viṣṇu He went to Vaikuntha (Ksheer-sāgar), with another form of Anant-Śeşa, He entered into Sarayu and went to Pātāla to support all the worlds, while with his own two-armed form of Lakshman, he went to his own eternal supreme Vaishnava-world (Sāket).
(Quoted From Brahma Rāmāyaṇam, Published in Gita Press Gorakhpur, Manas Piyush)
Śrī Vālmiki-Rāmāyaṇa, Śrī Rāmcaritamānas, etc are the story of that Paratpar Brahm Śrī Rām who is 31-- Ashesha-Karaṇa-Param (~ 6th Mangalācaraṇa Shloka, Śrī Rāmcaritamānas) - the Param-Kāraṇa who is beyond all causes, of whom no Kāraṇa (cause) is there', whose various manifestations are all the Viṣṇu-s. For example, Kāraṇodakaśāyī-Viṣṇu (Virāṭ-Purusa) is the Kāraṇa (cause) of all, Yet there is Kāraṇa (cause) of even that Kāraṇodakaśāyī-Viṣṇu, where the Kārana of Kāraṇa line ends, Of whom no other Kārana is present, that is 'Ashesha-Karaṇa-Param (अशेष-कारण-परम)' who is renowned by the name Śrī Rāma.
Although no difference exists between Him and his own various forms (Svāṁśa-s) like him, yet to magnify the display of Aiśvarya, Avatārī-Puruṣa may order his Avatāra-s (incarnations), It is not the reverse way. In Śrī Rāmacaritamānas, (Kṣirodakaśāyi-Viṣṇu) Śrī Lakshman orders the divine-tortoise incarnation (Kacchap), the divine-boar incarnation (Vārāha-deva) and Seşa (the great serpent who is the bed of Bhagavān Viṣṇu).
दिसिकुंजर कमठ अहि कोला । धरहु धरनि धरि धीर न डोला ॥ रामु चहहिं संकर धनु तोरा । होहु सजग सुनि आयसु मोरा ॥
"O elephants guarding the cardinal points, O divine tortoise incarnation, O serpent-king, and O divine boar-incarnation, steadily hold the earth that it may not shake. Śrī Rām seeks to break the bow of Shankara; therefore, listen to my command and be ready."
(Śrīmad Rāmāyaṇam 1.260.1-2)
Earth should not be deviated from its path as a result of the tremendous shock-waves generated from the breaking of the divine-bow of Shiva, therefore Virāt-Puruṣa Śrī Lakshman in whom Kṣirodakaśāyi Viṣṇu with all his four componentsare present commanded his incarnations, be ready and steadily hold the earth.
Śrī Lakshman Ji is the fourth component of Sanatan- Vishnu Bhagavan Śrī Rām, He is Ksheer-shāyī Vishnu or say the Sankarshana Vyuha. Bhagavan Śrī Rām is the original personality of godhead who dwells in the supreme abode of Saket (Brahm-Loka).
ततो विष्णोश्चतुर्भागमागतं सुरसत्तमाः । हृष्टा प्रमुदिताः सर्वे पूजयन्ति स्म राघवम् ॥
ततो tato then after; विष्णोश्चतुर्भागम् visnāś catur-bhāgam He the one in whom all four components of Ksheer-shāyī Vishnu are present, or the fourth component of Sanatan- Vishnu (i.e. Ksheer-shāyī Vishnu or Sankarshana Vyuha); आगतं āgatam — arrival; सर्वे sarvë – All; सुरसत्तमा: surasattamāh—the best of gods; हृष्टा hrstā—thrilled and joyful; प्रमुदिता: pramuditāh—delighted; पूजयन्ति स्म pūjayanti sma—worshiped; राघवं rāghavam—Lakshmana
"When Lord Lakshman in whom all four-parts of Vishnu (of Ksheer - Sāgar) are present (or the fourth component of Sanatan-Vishnu) arrived in the divine world (divam – Tripād-Vibhuti), then all best of gods (like Mahā-Shiva, Mahā-Brahmā, Mahā-Indra, etc) became thrilled, and delighted, and worshiped him (Lakshmana). "
(Śrī Vālmīki-Rāmāyaṇa 7.106.18)
viṣṇōś-catur-bhāgam means 'Ksheera-shāyī Vishnu's (Vishnoḥ) all four (Chatuh / Chatvāro) components (Bhāga) i.e. Ksheera-shāyī Vishnu himself (with his Shehsa + Shankha + Chakra) are present in whom that one' Lakshman was being worshiped by all great-gods after his arrival in the Divam. For example, Chaturbhujam means 'Chatuḥ Chatvaro (four) bhujā (arms) Yasmin/Yasya (in whom/ who has) Sa (He) Vishnuḥ (Vishnu) - the four arms are present in whom, He Lord Vishnu'. Similarly Caturyugam means - Caturṇām (four) Yugānām (Yugas) Samāhāraḥ (integrated collection)—the collection of all four Yuga is Chaturyugam' (not the one fourth /Chaturth of Yuga).
If one has Aagrah (insistence) for Vishnoḥ-catuh- bhāgam should be taken as Viṣṇōḥ-caturth-bhāgam [Catuḥ - four as Caturth - fourth], then It would still mean the fourth component of Sanatan-Vishnu (i.e. Ksheer-shāyī Vishnu or Sankarshana Vyuha), because Śrī Lakshman is the fourth part of Sanatan- Vishnu Bhagavan Śrī Rām, He is originally Śrī Lakshman in his form, therefore he is being seen and worshiped in his original form of Śrī Lakshman in the Divam (divine luminous transcendental world i.e. Tripad-Vibhuti). Actually, He just entered in the Aprakat-Ayodhya there itself. With other forms, He became Ksheera-shāyī Vishnu and with amsha Sankarshana-Vishnu.
In Śrī Vālmīki-Rāmāyaṇa, Śrī Lakshman doesn't give up his body or form at the end, He doesn't become Shesha, rather he arrives in the Divam (divine Brahm- Lok) with his own earlier form. His body is transcendental, He is eternally there in the supreme abode in his own eternal form of Lakshman, and manifests his another forms of Ksheer-shāyī Vishnu and Sankarshaṇa-Vishnu.
Similarly, all other brothers of Bhagavān Śrī Rāma entered in the supreme abode of Brahman, without giving up their earlier forms and bodies.
Whenever Supreme personality of Saket, Bhagavān Śrī Rām himself appears, then all Vishnu and components (Vyuha-s) of Vishnu become his younger brothers to serve him.
In simple terms, Shri Laksman ji is the Shesh Nag on which Vishnu sleeps.It is believed that he was the younger brother of Lord Rama in Treta Yuga. And there is a story that says, Shesh nag said to Vishnu that he wants to be an elder brother to Vishnu in his next Avatar. And Vishnu granted the wish. So in Dwapar Yuga, Balram was the elder brother to Lord Krishna.