Musnad Ahmad 1153:236

Yahya narrated to us, Hisham narrated to us, he said: My father informed me, from Aisha, from the Prophet, peace and blessings of Allah be upon him, that he entered upon her while a certain woman was with her. She mentioned her prayer, so he said: "Desist. You must do what you are capable of, for by Allah, Allah the Almighty does not grow weary until you grow weary. Indeed, the most beloved of religion to Allah is that which its practitioner persists in."