Mukhtasar Muslim

Sayyiduna Abu Musa (may Allah be pleased with him) narrates from the Noble Prophet (peace and blessings be upon him) that he said: Verily, Allah, the Mighty and Majestic, stretches out His hand at night so that the sinner of the day may repent, and He stretches out His hand during the day so that the sinner of the night may repent, until the sun rises from the west. (That is, after that, repentance will not be accepted.)