Musnad Ahmad 1153:1995

Yazid narrated to us, he said: Yahya informed us that Abu Bakr ibn Muhammad informed him, from Amrah bint Abd al-Rahman, from Aisha, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "Gabriel kept enjoining upon me [to treat] the neighbor [well], until I thought that he would make him an heir."