Examples of Prophet Mohammed's kindness

Once a beggar begged of him, and Mohammed took off his only coat and gave it to the beggar; then he had cold

Another time one of the needy asked him, and he gave him his only bread that he had; so he suffered hunger that night

Therefore, God revealed to him this Quran revelation 4: 79

مَّا أَصَابَكَ مِنْ حَسَنَةٍ ..إلخ

The explanation
(Whatever good visits you [Mohammed] it is of God;

whatever evil visits you is of yourself
[because you gave all what you had and then you suffered from cold and hunger.]

And We have sent you a messenger to men
[that they may take you an example, so don't give all what you have];

God suffices for a witness [to your work and good conduct.])

http://quran-ayat.com/shabaha/4.htm#79