Musnad Ahmad 993:1

Mu'awiyah ibn 'Amr narrated to us, Za'idah narrated to us, from Mansur, from Shaqiq, Samurah ibn Sahm narrated to us, he said: I stayed with Abu Hashim ibn 'Utbah while he was afflicted with the plague. Mu'awiyah entered upon him to visit him, and he wept. Mu'awiyah said to him: "What makes you weep? Is it a pain that distresses you, or is it for the world? For its purity has passed." He said: "It is not for either of those. But the Messenger of Allah (ﷺ) entrusted me with a covenant, and I wish I had followed it. The Messenger of Allah (ﷺ) said: 'Perhaps you will attain wealth that will be divided among people, and indeed, what suffices you of gathering wealth is a servant and a mount in the way of Allah.' And I have found [that I have] gathered."