The Prophet said:
'God has no mercy on one who has no mercy for others.'
'None of you truly believes until he wishes for his brother what he wishes for himself.'
'He who eats his fill while his neighbor goes without food is not a believer. '
'The truthful and trusty businessman is associated with the prophets the saints, and the martyrs.'
'Powerful is not he who knocks the other down, indeed powerful is he who controls himself in a fit of anger. '
'God does not judge according to your bodies and appearances but He scans your hearts and looks into your deeds.'
'A man walking along a path felt very thirsty. Reaching a well he descended into it, drank his fill and came up. Then he saw a dog with its tongue hanging out, trying to lick up mud to quench its thirst. The man saw that the dog was feeling the same thirst as he had felt so he went down into the well again and filled his shoe with water and gave the dog a drink. God forgave his sins for this action.' The Prophet was asked: 'Messenger of God, are we rewarded for kindness towards animals?' He said, 'There is a reward for kindness to every living thing.'
From the hadith collections of Bukhari, Muslim, Tirmidhi and Bayhaqi