God's Thankfulness?

On Wednesday evenings we are currently studying systematic theology and have been studying the communicable and incommunicable attributes of God.  In an effort to stay current with the events of the holidays, I decided to focus on the attribute of thankfulness to coincide with thanksgiving.  I found many passages on our thankfulness to God, but was unable to find any in which God was said to thank mankind.  This led to many discussions and deep thoughts before I stated the following at the start of our study last night:

Outside of the trinitarian relationship, God does not exhibit thankfulness to anyone.  If He did, He would have to be the beneficiary of mankind’s goodness . . . and we know there is nothing that man can do for God that benefits Him because He is complete in Himself.  

But we need to realize that God has given us instructions on thankfulness because it is an attribute that man must have.  God, the Father has also empowered us to be thankful because of what He has done for us and being thankless is the attitude of people who don't know God.

There was much discussion after this and I just wanted to see if anyone would like to weigh in on the issue . . .