Musnad Ahmad 1153:1945

Suwayd ibn ‘Amr narrated to us, he said: Aban ibn Yazid narrated to us, Yahya ibn Abi Kathir narrated to us, from Abu Salamah, from ‘Aishah, that the Messenger of Allah (may Allah bless him and grant him peace) used to, when he performed a prayer, persist in it. And the most beloved of prayers to him was that which one persists in, even if it were little. And he said: "Indeed, Allah the Almighty does not grow weary until you grow weary."