In Colossians 2:7 Paul writes that we are to walk in Christ, “having been firmly rooted and now being built up in Him and strengthened in your faith, just as you were taught, and overflowing with thanksgiving.” It is of note that “overflowing with thanksgiving” is added to this verse:
Paul is speaking of some fundamental qualities which we have in Christ: that we are rooted and built up and strengthened in Him — this is basic. Jesus is our foundation, and He is the One in whom we are then built up and grow. And then he adds that as a result we will be “overflowing with thanksgiving”!
This shows us that thanksgiving is no secondary or tertiary quality of the Christian life. It is to be at the heart of all we are and do. We are constantly to be giving thanks — “overflowing” with it — as a basic part of our lives. And the reason, of course, is what this verse talks about: because God has given us so much in Christ. He has given us a foundation in Him, built us up in Him, strengthened us in Him — NONE of which we deserved!
So a fundamental thanksgiving ought to be at the heart of every Christian’s life — especially for what God work in us in Christ Jesus. If our lives are not “overflowing with thanksgiving” then we are missing something big: either we do not appreciate what God has done for us in Christ — or we don’t have it at all!