Imam Sadiq (a.s) said: “Abraham (a.s) was the father of all hosts. Whenever he did not have any guests, he would leave the house, close the door, and take his keys and go to look for some guests. One night when he returned home, he saw a man or someone similar to a man in his house. He asked “O' servant of God! With whose permission did you enter this house?” He said: “With the permission of the owner of the house.” And he repeated it three times. Abraham (a.s) realized what had happened and praised the Lord. The guest said: “Your Lord has sent me to one of His servants whom He has chosen as His friend.” Abraham said: “Please introduce me to that friend (of God), so I get to know him before I die.” The man said: “You are that friend.” Abraham asked: “Why?” He said: “Since you never asked anyone for anything, and never turned down anyone who asked you for something.”