These verses remind me of one of my favorite words in the Newer Testament…”abide”. The word picture that John gives us in John 15, where Jesus talks about abiding, is that of a branch connected to a tree. Here Paul plays off the same metaphor.
“So walk in Him” – or as the NIV puts it “continue in Him”. In other words, stay connected. Don’t try to live this life apart from Him or you will find that you dry up, wither, and die.
“rooted and built up in Him” – We are to find our nourishment for a Spirit-fueled life in Him as we send out roots that soak up the nutrients we need – nutrients that He provides that will enable us to thrive and live healthy spiritual lives. It is when we try to be nourished by what the world provides that we find ourselves living anemic and wasted lives.
“established in the faith” – The idea of being established has to do with having a strong enough foundation so that we can withstand that which would seek to destroy us. As believers we need a strong and sturdy theological base to give us the support we need to stand throughout the storms of life. We need to thoroughly understand biblical themes such as God’s sovereignty, atonement and redemption, incarnation, grace, eschatology, sin, etc. so that we are not devoured by the falsities of the world and the schemes of the evil one.
“abounding in thanksgiving” – I think there is a very good reason why Paul includes this phrase among the others even though it doesn’t really fit with the metaphor. Gratitude is the primary way that we display to God that our sufficiency is in Him and not in ourselves. It is so easy to think that we are deserving of salvation because of our goodness. By “abounding in thanksgiving” we are expressing our neediness before God as well as demonstrating an attitude of humility – both of which combat the sinful tendency that we have towards pride and selfishness.
May the Father remind us often, in whatever ways are necessary, that it is only IN HIM that we find life and hope and joy.