Muwatta Imam Malik (Riwayat Ibn al-Qasim)

And with the same chain of narration, it is narrated from (Sayyiduna Abu Huraira, may Allah be pleased with him) that the Messenger of Allah, peace and blessings be upon him, said: "Whoever, after performing prayer, remains seated at his place of prayer, the angels continue to supplicate for him as long as his ablution is not broken. They say: «اللهم اغفر له اللهم ارحمه» O our Allah! Forgive him. O our Allah! Have mercy on him."