Is it mandatory to follow one Marga?

Question

Bhagavad Gita says:

Bg 12.9 — My dear Arjuna, O winner of wealth, if you cannot fix your mind upon Me without deviation, then follow the regulative principles of bhakti-yoga. In this way develop a desire to attain Me.

Bg 12.10 — If you cannot practice the regulations of bhakti-yoga, then just try to work for Me, because by working for Me you will come to the perfect stage.

Bg 12.11 — If, however, you are unable to work in this consciousness of Me, then try to act giving up all results of your work and try to be self-situated.

Bg 12.12 — If you cannot take to this practice, then engage yourself in the cultivation of knowledge. Better than knowledge, however, is meditation, and better than meditation is renunciation of the fruits of action, for by such renunciation one can attain peace of mind.

My question is: Out of Bhakti marga, Karma Marga, Jnana Marga do we need to strictly follow one particular marg to achieve the ultimate goal or can it be combination of them? Are they mutually exclusive?

Answer 1

These are not independent paths to Moksha, but rather steps that build upon one another and thereby lead to Moksha. This excerpt from Vedanta Desikan's Rahasyatraya Sara describes the progression of Karma Yoga, Jnana Yoga, and Bhakti Yoga:

Karma Yoga means the performance of certain kinds of Karmas or rites and duties as the result of knowledge acquired from the shastras in regard to the true nature of the Jivatma and the Paramatma. The rites and duties consist of the following: (1) Nitya Karmas or regular duties to be performed compulsorily (2) Naimittika Karma or rites to be performed compulsorily on special occasions (3) such Kamya Karma or rites as are optional and as have been chosen to be within one's ability.... Though these Kamya rites are ordained for obtaining specified fruits like Svarga, they have to be performed without any desire for those fruits.... Karma Yoga, either through Jnana Yoga or without it, becomes the means of having a vision of one's own self or soul, with the help of Yogic auxiliaries like Yama, Niyama, and Pranayama.

Jnana Yoga is the constant and uninterrupted contemplation, by one who has conquered his mind by Karma Yoga, of his Svarupa or essential nature or the self as being distinct from matter - his Svarupa which is the mode or Prakara of Ishwara in virtue of its relation to Him as his body or Sharira.... If a person has succeeded in obtaining a vision of his self by the practice of Yoga preceded by Karma Yoga and Jnana Yoga and if he escapes the snare of being attracted by the pleasure of enjoying this vision which is so great as to create a distaste for all sense-pleasures - then he begins the practice of Bhakti Yoga, which is the means for the attainment of the supreme goal of enjoying Bhagavan.

Bhakti Yoga is the special form of meditation which is of the form of unsurpassed love and which has, for its object, the essential nature and the like of Bhagwan who is not dependent on anyone else, who is not subject to the authority of anyone else and who does not exist for the fulfillment of the purpose of anyone else. Bhakti is of the form of a continuous stream of knowledge which is of the nature of uninterrupted memory like oil streaming down continuously; it has clearness similar to that of visual perception; it grows from strength to strength by being practiced every day until the day of journey to Paramapada and terminates in the remembrance [of Vishnu] of the last moment. The performance of the rites and duties of one's Varna and Ashrama is auxiliary to it, as it dispels sins that cause Rajas and Tamas which, like weeds, impede the growth of Sattvam so necessary for the expansion of knowledge.... Bhakti Yoga which has thus been prescribed as the means of obtaining Moksha has been called Parabhakti. It produces in its turn an eager desire and determination to see the Lord[.]... By this keen desire alone, he wins the grace of Bhagavan who awards him with a perfect visual perception of himself for the time being. This visual perception is called Parajnana. From this perfect vision of the Svarupa of the Lord is born an excessive an unsurpassed love for the Lord similar to that felt by a man suffering from great thirst at the sight of a tank. This is called Paramabhakti. Paramabhakti produces an eager desire and determination to enjoy the Lord without any limitations, as the Bhakti feels that it is impossible to live any longer without the experience of the Lord[.]... It causes an excessive eagerness in the Lord to give him Moksha immediately and makes him attain Moksha after quenching his great thirst for union.

Whew! In any case, just because these three don't form independent paths to Moksha doesn't mean there aren't any independent paths to Moksha. There is a much easier alternative to this entire path, and it's called Sharanagati. Krishna describes it in chapter 18 of the Bhagavad Gita:

sarva-dharmān parityajya mām ekaṁ śaraṇaṁ vraja |
ahaṁ tvāṁ sarva-pāpebhyo mokṣayiṣyāmi mā śucaḥ ||

Abandon all varieties of religion and just surrender unto Me. I shall deliver you from all sinful reactions. Do not fear.

Answer 2

The scriptures say that all these 3 paths are valid methods to Moksha. So, one can choose one depending on one's aptitudes.

And, it is not like that if one follows any one of them, one can not follow any other. A combined approach is also possible as stated in the following passages (read the 2nd blockquote, which clearly talks about the combined approach) from the Devi Bhagavata Purana:

The Himâlayâs said :-- "O Mother! Now describe your Bhakti Yoga, by which ordinary men who have no dispassion get the knowledge of Brahma easily. 2-10. The Devî said:--"O Chief of Mountains! There are three paths, widely known, leading to the final liberation (Moksa). These are Karma Yoga, Jñâna Yoga and Bhakti Yoga. Of these three, Bhakti Yoga is the easiest in all respects; people can do it very well without incurring any suffering to the body, and bringing the mind to a perfect concentration.

From Devi Bhagavatam's Book 7.

And, they are not mutually exclusive.

The highest path is of course the Jyana path but that's hard to follow from the start. So, we have to follow a definite route as mentioned by Sri Devi herself in the following passage:

By My Grace, you will no doubt be able to get the Final Liberation. Whoever is entirely attached to Me, thinking Me as the Highest, is the foremost amongst the Bhaktas. I promise that I will certainly deliver him from this ocean of the world. O King of mountains! Meditation with Karma and Jñâna with Bhakti will lead one to Me. Only the work alone will fail to get one to Me. O Himavan! From Dharma arises Bhakti and from Bhakti arises the Highest Jñâna. What are said in the S'ruti and Smriti S'astras the Maharsis take that as the Dharma; and what are written in other S'astras, they take them to be Dharmâbhâsa (the Shadow or reflection of Dharma).

So, before choosing any of the paths, one needs to follow the path of Dharma. Because, Dharma is foremost, as it lies at the root of everything. With that Bhakti will arise and the rest they say is easy.