Colossians 1:23 (NKJV)

if indeed you continue in the faith, grounded and steadfast, and are not moved away from the hope of the gospel which you heard, which was preached to every creature under heaven, of which I, Paul, became a minister.

Explanation

This verse is often misinterpreted as requiring believers to ‘continue’ in their faith and not turn away from the gospel’s hope, or else they will be in danger of being thrown into hell.

However the opposite is true, this verse is a positive statement that says true believers who have been reconciled will persevere in faith and obedience.

This is solely due to the fact that they are made new creatures (2 Cor. 5:17) with a new disposition in their hearts that desires obedience, loves God, hates sin, and is energized by the Holy Spirit (cf. John 8:30–32; 1 John 2:19).

True believers will remain steadfast in the gospel (1 Cor. 3:11) and faithful by the enabling grace of God (Phil. 1:6; 2:11–13), running the race with persevering faith and fixing their eyes on Jesus (Hebrews 12:1-2), rather than defect from it.

Essentially, Paul was saying, if you continue in the faith (which you will certainly do if you are saved) it is evident of truth of the gospel working within you. Paul is not casting doubt on our salvation, rather he is stating that someone who is genuinely saved will most certainly continue in it.

It is not a question of “if you do this or that, you will be saved or continue to be saved”; it is simply a statement that “if you are saved you will continue in the faith.”

The mark, of someone who is saved is that they maintain their confession of faith until the end of their lives.

Salvation is not a one-time prayer you perform at an altar call ; salvation is a posture of repentance and faith that you begin in a moment and maintain for the rest of your life.

The perseverance of a persons faith is not what saves them rather it is an evidence that the persons faith is genuine and that they are truly saved.

It should also be noted that the verse is not not saying that a believer will never “backslide” (honestly, most of us have backslidden to one degree or another) but the individual who backslides will not persist or remain indefinitely in their backslidden condition.

The Christian walk of spiritual growth and life is not an easy one. While we are transformed into a new nature at the point of salvation we are still called to “workout  our salvation.” 

Our mind, heart, and will must be fully engaged. Our minds should feed on Christ and His Word. Our hearts are to focus on Him in love. Our wills are to submit to Him, taking both their practice and pattern from His example.

Our present faith leads to present results just like our present drinking is for ‘present thirst. We must fill our lives every day from Him.