How can one forget the past, bad deeds, and sins, and return to Allah?

However much a person may transgress against himself, Allah forgives all sins for the sincere penitent. The transgressor must not despair but rather repent with a sincere repentance that fulfills the conditions (abandoning the sin, regretting it, resolving not to return to it, and restoring rights).

As for forgetting the sin, the people of spiritual conduct have differed on this: some believed that forgetting it is better for the clarity of one's time with Allah, while others thought that remembering it is better for the brokenness and humility it produces.

The correct approach is to differentiate: - If the servant feels a sense of claim, conceit, or forgets Allah's favor, then remembering the sin is more beneficial for him to make him feel his poverty and shortcomings. - However, if he is in a state of witnessing Allah's favor upon him, his need for Him, and Allah's love, and the lights of the Divine Names and Attributes have illuminated his heart, then forgetting the sin and turning away from it is more appropriate and beneficial for him, so that this state does not disappear from him and he returns to a lower condition.