All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. Indeed, there is a Hadeeth with this meaning. It was narrated that on the Day of Judgment, Allaah The Almighty will gather all mankind and ask one of His slaves: "Did you thank so-and-so for the favor that he did for you?" The slave will reply that he only thanked Allaah The Almighty because He is the source of all bounties. Allaah The Almighty will tell that slave that "he did not thank Him because he did not thank the one through whom he attained the favor". [Al-Bayhaqi: Dha‘eef (Weak)] Even though this Hadeeth is Dha'eef, its meaning is correct. It was narrated on the authority of Abu Hurayrah that the Prophet, sallallaahu ‘alayhi wa sallam , said that "the one who does not thank people for the good things they do for him is not thanking Allaah The Exalted". [Ahmad, Abu-Daawood & At-Tirmithi] Al-Khattaabi stated that this Hadeeth can be interpreted in two ways: 1- The person who is ungrateful to people for the good things they do for him will also be ungrateful for the good done to him by Allaah The Almighty. This is the predominant interpretation. 2- Allaah The Almighty does not accept thanks for His blessings unless the slave also thanks people for the good things they do for him. Allaah Knows best.