Musnad Ahmad 30:1775

'Abd al-Razzaq narrated to us, Sufyan informed us, from Ibn Dhakwan, from 'Abd al-Rahman al-A'raj, from Abu Hurayrah, who said: The Messenger of Allah (may Allah bless him and grant him peace) said: "Delaying payment by the wealthy is injustice. And if one of you is referred to a solvent person, let him accept the referral."