Musnad Ahmad 27:61

Isma'il narrated to us, Ayyub informed us, from Nafi', from Ibn 'Umar, who said: The Messenger of Allah (peace and blessings of Allah be upon him) said: "The likeness of you and the likeness of the Jews and the Christians is like a man who employed workers and said: 'Who will work from the morning prayer until midday for a qirat for each?' So the Jews worked. Then he said: 'Who will work for me from midday until the afternoon prayer for a qirat for each?' So the Christians worked. Then he said: 'Who will work for me from the afternoon prayer until sunset for two qirats for each?' So you are those who worked. The Jews and the Christians became angry and said: 'We did more work and received less pay.' He said: 'Did I wrong you in any of your rights?' They said: 'No.' He said: 'Then it is only My bounty, which I bestow upon whom I will.'"