It is narrated from Sayyiduna Ali (may Allah be pleased with him) that the Messenger of Allah (peace and blessings be upon him) said: "When a person remains seated on his prayer mat after the prayer, the angels send blessings upon him, and the angels’ blessing is this supplication: O Allah! Forgive him, O Allah! Have mercy on him. In the same way, if he sits waiting for the next prayer, the angels also send blessings upon him, and their blessing is this supplication: O Allah! Forgive him, O Allah! Have mercy on him."