Once, Prophet Muhammad (PBUH) was going somewhere. On His way He came across a man who wanted to sell his camel. They agreed on a price. Holy Prophet (PBUH) had no money with him and asked the man to accompany him to his home for payment.
As they were on their way, another man asked the price of the camel. He was told that the camel was already sold to Holy Prophet (PBUH) but the wayfarer offered a better price and the seller decided to sell the camel to him.
Prophet Muhammad (PBUH) said that while the camel was already sold, it was wrong to sell it to another man and breaking the already made agreement. The seller denied any previous agreement.
As this commotion was going on, other people started gathering around. Prophet Muhammad (PBUH) explained the passers by the situation. People asked, if Prophet Muhammad (PBUH) had any proof, to which He replied that no witness was present at the time of the agreement. They all replied in unison that they cannot help Him without any witnesses of agreement. A close companion of Prophet Muhammad (PBUH) was passing from that place as well. When he inquired what was going on, he said, the Prophet (PBUH) was not lying and camel dealer is not telling the truth.
The holy Prophet (PBUH) asked the companion that how did he come to this conclusion when he wasn’t present at the time of agreement between the camel seller and Prophet Muhammad (PBUH)? The companion replied, “O Prophet Muhammad (PBUH), you told us about Allah. We believed you, without seeing him. You said that Holy Quran is the word of the Almighty and we believed it as well. You gave us the concept of heaven and hell, and we again deemed it truth. We believed all those things which we have not witnessed. So its impossible that Prophet Muhammad (PBUH) will lie about anything”.