Colossians 1:21-23
21 And you, that were sometime alienated and enemies in your mind by wicked works, yet now hath he reconciled
22 In the body of his flesh through death, to present you holy and unblameable and unreproveable in his sight:
23 If ye continue in the faith grounded and settled, and be not moved away from the hope of the gospel, which ye have heard, and which was preached to every creature which is under heaven; whereof I Paul am made a minister;
Verse 22 above is often interpreted as describing eternal justification, and since it is predicated on doing what verse 23 says - "continuing in the faith grounded and settled" - this passage is often taken as a proof for the doctrine that a believer must persevere in faith and good works in order to be eternally saved.
Is this a valid interpretation of this passage?
This passage is one of many exhortations to experiential holiness - which Christ also died to achieve in us. Christ's work did not only secure the positional holiness that we have by virtue of the New Birth (Ephesians 4:24, Romans 11:16: 1 Corinthians 3:17: 1 Peter 2:5, 2:9, etc.), but to as many as walk in the Spirit, it also secured a practical and experiential holiness, even in this present time.
Some similar exhortations include:
Romans 12:1
1 I beseech you therefore, brethren, by the mercies of God, that ye present your bodies a living sacrifice, holy, acceptable unto God, which is your reasonable service.
2 Peter 3:11
11 Seeing then that all these things shall be dissolved, what manner of persons ought ye to be in all holy conversation and godliness,
Ephesians 5:27
27 That he might present it to himself a glorious church, not having spot, or wrinkle, or any such thing; but that it should be holy and without blemish.
1 Thessalonians 3:12-13
12 And the Lord make you to increase and abound in love one toward another, and toward all men, even as we do toward you:
13 To the end he may stablish your hearts unblameable in holiness before God, even our Father, at the coming of our Lord Jesus Christ with all his saints.
1 Peter 1:15-16
15 But as he which hath called you is holy, so be ye holy in all manner of conversation;
16 Because it is written, Be ye holy; for I am holy.
All of the above are admonishments to live out the reality of our positional holiness, in our Christian walk. That is one of the eternal designs for the purpose of the Church, here on earth (Ephesians 1:3-4, Matthew 5:14, Philippians 2:15).
We also see, in the verse in question, and 1 Thessalonians 3:13 above, the concept of being "unblameable". Even though positionally speaking, every Christian is already "blameless" (Romans 4:6-8, 8:33, John 3:18, 5:24, Colossians 1:14, 2:13, Hebrews 8:12, 10:17, Ephesians 1:7, etc.), this, too, often refers to being blameless in experience:
Philippians 2:14-16
14 Do all things without murmurings and disputings:
15 That ye may be blameless and harmless, the sons of God, without rebuke, in the midst of a crooked and perverse nation, among whom ye shine as lights in the world;
16 Holding forth the word of life; that I may rejoice in the day of Christ, that I have not run in vain, neither laboured in vain.
2 Peter 3:14
14 Wherefore, beloved, seeing that ye look for such things, be diligent that ye may be found of him in peace, without spot, and blameless.
1 Timothy 5:7
7 And these things give in charge, that they may be blameless.
In addition to the examples given above, the fact that being "blameless" is given as a requirement for becoming a bishop and a deacon (1 Timothy 3:2, 3:10, Titus 1:6-7), is yet more proof that this is not always in reference to the positional justification that all Christians have. If it were, it wouldn't need to be called out as a requirement.
So, what we see in the passage in question is a testament to the fact that being found blameless, and holy, and unreproveable in the Lord's sight, in the experiential sense, is not a guarantee, being conditioned upon "continuing in the faith grounded and settled, and not being moved away from the hope of the gospel" (Colossians 1:23).
Living in experiential holiness certainly has consequences in this life, namely, avoiding chastening (Hebrews 12:6), and also, as mentioned above, fulfilling the eternal purpose of God in the Church, being the light of the world. Also, when appearing before Christ at the Judgment Seat of Christ, the extent to which a believer walked in holiness will be a determining factor in deciding their rewards (1 Corinthians 3:11-15), as is covered at length in this article.
A common error in interpreting Scripture, is trying to force every use of a word to mean the exact same thing. This simple mistake in reading comprehension, which requires one to totally ignore context, is the root of the misinterpretation of the passage in question.
This passage does not teach works Salvation, because no passage in Scripture teaches such a thing. Rather, it's an exhortation to experiential holiness - one of many such passages in the New Testament - and is actually proof that such a thing is not guaranteed, which also runs contrary to what is taught by most brands of works Salvation masquerading as Salvation by faith alone.