Musnad Ahmad

It is narrated from Sayyiduna Ibn Umar (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "The example of you and the Jews and Christians is like that of a man who hired some laborers and said, 'Who will work from the morning prayer until midday for one qirat?' So the Jews worked from the morning prayer until midday. Then he said, 'Who will work from midday until the afternoon prayer for one qirat?' So the Christians worked. Then he said, 'Who will work from the afternoon prayer until sunset for two qirats each?' Remember, you are those who worked during this period. But the Jews and Christians became angry and said, 'Our labor was so much and the wage so little?' Allah said, 'Did I fall short or neglect in giving you your right in any way?' They replied, 'No.' Allah said, 'Then this is My grace, I bestow it upon whom I will.'"