He desired for them to give thanks to the Father who made them able to partake of His inheritance. To thank the one who delivered them from the power of darkness into the kingdom of His son. The one in whom we have redemption and forgiveness of sin through His blood. He went on to remind them of who Jesus really was and still is.
Paul's desires and prayers for the people of His day should be ours for the people of our day. Everything Paul prayed, we can pray. The Lord is the same, He hasn't changed. He can know what the will of God is. We can walk worthy of the Lord, with His help. We can be fruitful and strengthened with His power. And we can certainly give thanks to God because we have so much to be thankful for. It would take a long time to thank the Lord for all He has done. But praise God we will have the time because we will be praising Him through the countless ages of eternity.