The Messenger of Allah ﷺ said, "There is no group that gathers to remember Allah, seeking nothing by it except His face, but a caller calls out to them from the heavens, 'Rise, you have been forgiven. Your evil deeds have been transformed into good ones.'"
عن رسول الله ﷺ قال: ما من قوم اجتمعوا يذكرون الله لا يريدون بذلك إلا وجهه إلا ناداهم مناد من السماء: أن قوموا مغفورا لكم، قد بدلت سيئاتكم حسنات.
Ahmad (12453) narrated it from Muhammad bin Bakr, who said, Maymun Marii told us, who said, Maymun bin Siyah told us, from Anas, and he related it. Its chain of transmission is hasan on account of Maymun Marii, who is Ibn Musa, and Maymun bin Siyah, for both of them are graded hasan in hadith transmission. Bazzar narrated it in Kashf Astar (3061), and Abu Yaala (4141), both by another route from Maymun bin Siyah with the same wording.