"Paradise and the Fire debated. Paradise said: 'The weak and the poor shall enter me,' and the Fire said: 'The tyrants and the proud shall enter me.' So He said to the Fire: 'You are My Punishment, I take vengeance through you from whom I will,' and He said to Paradise: 'You are My Mercy I show mercy through you to whom I will.'"
Jami` at-Tirmidhi Book 38, Hadith 39