There are two phrases in v. 10 that call for our careful attention.
(1) Observe that Paul speaks of the need for us to walk "worthy of the Lord." The apostle uses similar language in a number of texts. For example, in Philippians 1:27 he exhorts the believers in that city to let their "manner of life be worthy of the gospel of Christ." In Ephesians 4:1 he urges believers "to walk in a manner worthy of the calling to which you have been called." Again, in 1 Thessalonians 2:12 he declares that he earlier encouraged them "to walk in a manner worthy of God." This is almost identical to the language of John in 3 John 6b – "You will do well to send them on their journey in a manner worthy of God."
Someone might get the wrong idea from this, especially given the strong emphasis throughout Colossians 1 on the necessity of good works and bearing fruit and the like. Paul is most assuredly not saying that by our efforts and deeds and commitment we prove ourselves to be worth God or worth the salvation he offers, as if it were by our merits that we gain eternal life. In other words, neither Paul nor John is suggesting that we should strive to earn a place in God's favor or by our good deeds put him in our debt such that he is obligated to acknowledge our efforts and reward us accordingly. This is the opposite of the gospel of grace that we find throughout Scripture.
The focus in Ephesians 4:1 is on the worth of our calling, not our personal worth. The focus in Philippians 1:27 is on the worth and value of the gospel of Christ, not the people who believe in it. In both 1 Thessalonians 2:12 and 3 John 6, the point is that God is worthy of our complete and unqualified dedication and devotion. And here in Colossians 1:10, the idea isn't that we are worthy by virtue of how we walk but that we should walk in a way that reflects or displays how much he is worthy of such obedience on our part.
Our great Triune God and the marvelous and undeserved kindness that is ours in the gospel are of such infinite value, so exalted and beautiful and full of glory, that we should always live in such a way that it be known. Our lives, by his grace, should reflect positively on God. People should walk away from having observed us saying, "My goodness, what an incredible God he/she believes in!" Our aim isn't to evoke from them praise and admiration of who we are, but praise and admiration of who he is! Jesus, the cross, the gospel of salvation by grace alone through faith alone, are worthy of lives that reflect on their value, not ours.
(2) The second thing to note here is that a life worthy of the Lord is one that is "fully pleasing to him" in all things.
The more literal rendering of this phrase would be something like, "to every type/sort of pleasing," or "to please him in all respects." Whereas it is God the Father who fills us with the knowledge of his (God the Father's) will (v. 9), the "Lord" (v. 10) whom we please is probably Jesus.
This is the only place in the New Testament where the noun "pleasing" occurs, but the verb occurs in such texts as Romans 8:8 ("those who are in the flesh cannot please God"); 1 Cor. 7:32 ("how to please the Lord"); and 1 Thess. 2:4 ("to please God who tests our hearts"). See also Rom. 15:1-2; Gal. 1:10; 1 Thess 2:15; 4:1.
In secular Greek this particular word most often signified "the behavior by which one sought to gain a favor, and therefore was most often employed with a negative connotation meaning 'obsequiousness'" (O'Brien, 22). To put it in common, somewhat vulgar language, it meant something along the lines of "brown-nosing".
My reason for highlighting the word here in Colossians 1:10 is two-fold.
First, it reminds us again that good works are pleasing to God! They make God happy. They evoke his pleasure. They incite joy in his heart. God is not devoid of emotions. He feels great delight in good deeds (and displeasure in bad ones; see below).
Of course, we must never forget the incredible words of Hebrews 13:20-21 where the author of that epistle prays, "Now may the God of peace who brought again from the dead our Lord Jesus, the great shepherd of the sheep, by the blood of the eternal covenant, equip you with everything good that you may do his will, working in us that which is pleasing in his sight, through Jesus Christ, to whom be glory forever and ever. Amen" (cf. also Phil. 2:12-13).
Thus, when God takes pleasure in our good deeds he is rejoicing in the work of his own grace and power! He is the one who works in us what pleases him. Thus, in rewarding our works God is crowning his own grace!
The second thing to keep in mind is that if our good works please him, our bad ones displease him. On more than one occasion the book of Proverbs speaks of certain deeds as being an "abomination" to the Lord. I can't think of anything more horrendous than a life that God regards as an abomination.
The great difference, of course, is that all good works that please him are the result (ultimately) of his gracious energy in us, whereas all bad works that displease him are our responsibility, for which we shall given an account.
Hoping to please him,