Colossians 1:23

if indeed you continue in the faith, stable and steadfast, not shifting from the hope of the gospel that you heard, which has been proclaimed in all creation under heaven, and of which I, Paul, became a minister.

-Colossians 1:23

[and He will do this] if you continue in the faith, well-grounded and steadfast, and not shifting away from the [confident] hope [that is a result] of the gospel that you have heard, which was proclaimed in all creation under heaven, and of which [gospel] I, Paul, was made a minister.

-Colossians 1:23 (AMP)

We know that it is not according to works that we are saved, but by grace through faith.

For by grace you have been saved through faith. And this is not your own doing; it is the gift of God, not a result of works, so that no one may boast.

-Ephesians 2:8-9

So, when we come to passages like this one in Colossians, it may seem like salvation by works.  It does say that Jesus' reconciling and presenting us blameless hinges on whether or not we continue in the faith.  It sounds like a work we need to do in order to be saved.  So, how do we reconcile these two opposite things?  On one hand, salvation is by grace through faith.  On the other hand, it seems as if we will only be saved if we continue in faith.  I've been listening to a lot of music lately, so some of the words are fresh in my mind:

"But I thought salvation's through faith alone?
Yes, but this faith is shown by those who make it home
Because Christ words are clear
Those who are saved endure to the end and persevere"

-Pressing Into the Kingdom, Timothy Brindle

"Killing Sin is not a prescription of how to be forgiven.It’s a description of the Christian who is forgiven by trusting in the risen Christ who took our wrath and affliction.
Killing Sin is not a prescription of how to be forgiven but it’s a description of the Christian who is forgiven and the Spirit now convicts them to put off and kill their sick sin"

-Fruit Inspection, Timothy Brindle

If you are saved, you are one who will persevere.  The endurance is not how to be saved, but it's what saved people do.  Saved people persevere to the end.  Let's be reminded of the hope of the gospel and endure to the end.