Albert Barnes Commentary Colossians 2:7

"rooted and builded up in him, and established in your faith, even as ye were taught, abounding in thanksgiving." — Colossians 2:7 (ASV)

Rooted—in him. As a tree strikes its roots deep in the earth, so our faith should strike deep into the doctrine concerning the Saviour. See this phrase explained in the parallel passage in Ephesians 3:17.

And stablisheth in the faith, as ye have been taught. That is, by the founders of the church and by those faithful ministers who had succeeded them. See the notes on Colossians 1:7.

Abounding therein with thanksgiving. Expressing overflowing thanks to God that you have become acquainted with truths so precious and glorious. If there is anything for which we should be thankful, it is for the knowledge of the great truths concerning our Lord and Saviour.