In the mythology of the Puranas and the epics, the picture of sins (pāpa ) and virtue (pūnya) that emerges is mostly based on the superstitions and is not comprehensive to present a unequivocal, logical, argumentative answer to your question. However, Vedas presents an answer that appeals to logic and legal philosophies.
Before dealing with the question of pāpa or pūnya it is pertinent to deal with the motivation behind the karma. Because without knowing what the type of karmas are, what the cause of karmas is, it is not possible to establish the link between the karma and the restrain required on the karma.
There are two theories regarding the karma that can be delineated 1) free-will or 2) lack thereof.
2) In Ṛg Veda Vasiṣṭha is praying to Varuṇa (7.86.6)
न स स्वो दक्षो वरुण ध्रुतिः सा सुरा मन्युर्विभीदको अचित्तिः । अस्ति
ज्यायान्कनीयस उपारे स्वप्नश्चनेदनृतस्य प्रयोता ॥६॥
na sa svo dakṣo varuṇa dhrutiḥ sā surā manyurvibhīdakoacittiḥ asti
jyāyān kanīyasa upāre svapnaścanedanṛtasya prayotā
The sin does not happen because of the defects of the doer. It happens due to illusion, anger, and ignorance, the impetus coming from the Devas. Even in the dreams it is impetus from the gods that sin is committed.
Śāyana comments (paraphrased above) to this verse in original are:
हे वरुण सः स्वोदक्षः पुरुषस्य स्वरूपवद्बलं पापपवृत्तौ कारणं न भवति किं
तर्हि श्रुतिः स्थिरा उत्पत्तिसमय एव निर्मिता दैवगतिः कारणम् …एवं च सति
स्वप्नश्चन स्वप्नोपि अनृतस्य पापस्य प्रयोता प्रकर्षेण मिश्रयिता भवति
इदिति पूरकः स्वप्ने कृतैरपि कर्मभिर्बहूनि पापानि जायन्ते किमु वक्तव्यं
जाग्रतिकृतैः कर्मग्निः पापान्युत्पद्यन्त इति ।
That is to say, it is the God who provides the impetus to the human to commit sin.
Durgācharya also commenting on the Nirūktā (1.4) holds a similar opinion.
1) The free-will is best expressed in the Aṣṭādhyāyī of the celebrated grammarian Pāṇini (1.4.54)
स्वतन्त्रः कर्ता ,
which means that human is free to choose what karmas he should perform.
Now coming back to your question.
The Vedas clearly prescribe that the results of the sins must be borne. There is a story in the Ṛg Veda (1.35.9)
हिरण्यपाणिः सविता विचर्षणिरुभे द्यावापृथिवी अन्तरीयते । अपामीवां बाधते
वेति सूर्यमभि कृष्णेन रजसा द्यामृणोति ॥९॥
hiraṇyapāṇiḥ savitā vicarṣaṇir ubhe dyāvāpṛthivī antar īyate |
apāmīvām bādhate veti sūryam abhi kṛṣṇena rajasā dyām ṛṇoti ||
This a story which illustrates that even gods must bear the results of their sins. Once the gods performed a fire ceremony. There are many oblations to be performed in the fire ceremony. Savitṛ did not recite the required chants before raising the pot in the hand and as a result, the hand of Savitṛ fell. Adhvaryū was scared to see this and made a hand of the gold for Savitṛ A similar fate awaits Bhaga who ate from the offering pot without properly inspecting the contents and as a result, lost his eyesight. Pushan had to pay the price of tasting the contents by losing his teeth.
This story is also mentioned in Kaushitaki Brahmana (6.13)
अथ यत्र ह तद् देवा यज्ञम् अतन्वत । तत् सवित्रे प्राशित्रम् परिजह्रुः ।
तस्य पाणी प्रचिच्छेद । तस्मै हिरण्मयौ प्रतिदधुः । तस्माद्द् हिरण्य
पाणिर् इति स्तुतः
Yāska, the commentator of the Nighantu (Vedanga) also alludes to this story (3.11, 6.11).
The moral of the story is that it does not matter what your position is the punishment for the sins must be borne.
Vasiṣṭha says in his Dharma sutras (6.3) that Vedas cannot purify the person who is not mindful of his actions.
Adityās are implored in the Ṛg Veda (8.18.10) to keep the supplicant away from the sins
अपामीवामप स्रिधमप सेधत दुर्मतिम् । आदित्यासो युयोतना नो अंहसः ॥१०॥
From the viewpoint of the Veda, it is to be understood that there is no pardon for the sinner.
Through the mantras स नः पितेव (1.1.9), यो नः पिता जनिता (10.82.3) God has been remembered as mother or father but justice and mercy should not be considered as pitted against each other in the teachings of Veda. On the contrary, justice and mercy go together in the Vedas.