Sahih Bukhari Volume 003, Book 036, Hadith Number 471.
Narated By Abu Musa : The Prophet said, "The example of Muslims, Jews and Christians is like the example of a man who employed laborers to work for him from morning till night for specific wages. They worked till midday and then said, 'We do not need your money which you have fixed for us and let whatever we have done be annulled.' The man said to them, 'Don't quit the work, but complete the rest of it and take your full wages.' But they refused and went away. The man employed another batch after them and said to them, 'Complete the rest of the day and yours will be the wages I had fixed for the first batch.' So, they worked till the time of 'Asr prayer. Then they said, "Let what we have done be annulled and keep the wages you have promised us for yourself.' The man said to them, 'Complete the rest of the work, as only a little of the day remains,' but they refused. Thereafter he employed another batch to work for the rest of the day and they worked for the rest of the day till the sunset, and they received the wages of the two former batches. So, that was the example of those people (Muslims) and the example of this light (guidance) which they have accepted willingly.