4:110An-Nisaa

Whatever you assert and whatever you call to is indeed good. But if you inform us that there is atonement of our past deeds (then we would embrace Islam). Then it was revealed: And those who call not unto another god along with Allah and slay not any soul which Allah has forbidden except in the cause of justice, nor commit fornication; and he who does this shall meet the requital of sin. Multiplied for him shall be the torment on the Day of Resurrection, and he shall therein abide disgraced, except him who repents a believes and does good deeds. Then these! for the Allah shall change their vices into virtues. Verily Allah is Ever Forgiving, Merciful (xxv. 68-70). Say thou: O my bondsmen woo have committed extravagance against themselves despair not of the Mercy of Allah I Verily Allah will forgive the sins altogether. He is indeed the Forgiving, the Merciful (xxxix. 53).

The Prophet (ﷺ) said: If anyone says: "I ask pardon of Allah than Whom there is no deity, the Living, the eternal, and I turn to Him in repentance," he will be pardoned, even if he has fled in time of battle.

He who seeks repentance (from the Lord) before the rising of the sun from the west (before the Day of Resurrection), Allah turns to him with Mercy.

“Whoever takes the wrongdoer's side in a dispute or supports wrongdoing, he will remain subject to the wrath of Allah until he gives it up.”

“Whoever commits a sin in this world and is punished for it, Allah (STW) is too just to repeat the punishment for his slave (in the hereafter). And whoever commits a sin in this world and Allah conceals him, Allah is too generous to go back to something that He has pardoned.”