As noted by Piper, thanksgiving is essential to the Christian life and the church’s life because at the heart of thanksgiving there are two things:
Thanksgiving is making God look as big as he really is. “Givers are more glorious than receivers are.
Benefactors are more glorious than beneficiaries are. When we thank God, we acknowledge and display that he is the giver; he is the benefactor. We pay him a high compliment…. Therefore, when gratitude springs up in the human heart toward God, he is magnified as the wealthy source of our blessing. He is acknowledged as giver and benefactor and therefore as glorious. But when gratitude does not spring up in our hearts at God's great goodness to us, it probably means that we do not want to pay him a compliment; we do not want to magnify him as our benefactor.
Thanksgiving always takes away from us. Thanksgiving detracts from our own glory.
For genuine gratitude admits that we are beneficiaries of an unearned bequest; we are cripples leaning on the cross shaped crutch of Jesus Christ; we are paralytics living minute by minute in the iron lung of God's mercy.
1 Verse 4 shows that this is what Paul is doing.
3 We always thank God, the Father of our Lord Jesus Christ, when we pray for you,