The Messenger of Allah ﷺ said, "A Muslim servant remains in prayer as long as he is sitting in his place of prayer, kept there only by his anticipation of the next prayer. The angels keep saying, 'Allah, forgive him. Allah, have mercy on him,' as long as he does not break his ablution."
حدثنا عبد الله بن الحارث عن الضحاك عن سعيد بن أبي سعيد المقبري
أن رسول الله ﷺ قال لا يزال العبد المسلم في صلاة ما دام في مصلاه قاعدا ولا يحبسه إلا انتظار الصلاة والملائكة يقولون اللهم اغفر له اللهم ارحمه ما لم يحدث
Its chain of transmission is sahih. It occurred previously at 10447. Abdullah bin Harith bin Abdul-Malik, Abu Muhammad, the Makhzumi, the Makki, is trustworthy, and his hadith is found in the collection of Muslim and the four (Sunan compilers).