Can you show me from the context he is not talking about salvation.
The context doesn't support the idea of rewards.
22 yet He has now reconciled you....23 if indeed you continue in the faith
The context is not salvation, but being grounded and settled!
Colossians 1:23 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;
Paul is addressing saints in Colosse (Colossians 1:2 KJV): those who have faith in Christ Jesus (Colossians 1:4 KJV), to know of the hope that is laid up for them in heaven having heard before the word of the truth of the gospel (Colossians 1:4-5 KJV).
To be grounded and settled and be not moved away from the hope of the gospel is to be filled with the knowledge of God’s will in all wisdom and spiritual understanding,
Colossians 1:9 For this cause we also, since the day we heard it, do not cease to pray for you, and to desire that ye might be filled with the knowledge of his will in all wisdom and spiritual understanding;
to walk worthy of the Lord (as Paul beseeched the Ephesians Ephesians 4:1-6 KJV) unto all pleasing, being fruitful in every good work, and increasing in the knowledge of God
Colossians 1:10 That ye might walk worthy of the Lord unto all pleasing, being fruitful in every good work, and increasing in the knowledge of God;
God’s will is that all men be saved, AND to come unto the knowledge of the truth!
1 Timothy 2:4 Who will have all men to be saved, and to come unto the knowledge of the truth whereunto Paul was ordained a preacher, and an apostle, a teacher of the Gentiles in faith and verity (1 Timothy 2:7 KJV), a minister, according to the dispensation of God which was given to him for us, to fulfil the word of God (Colossians 1:26 KJV)
Colossians 1:26 Even the mystery which hath been hid from ages and from generations, but now is made manifest to his saints:
Colossians 1:27 To whom God would make known what is the riches of the glory of this mystery among the Gentiles; which is Christ in you, the hope of glory:
Colossians 1:28 Whom we preach, warning every man, and teaching every man in all wisdom; that we may present every man perfect in Christ Jesus:
Colossians 1:29 Whereunto I also labour, striving according to his working, which worketh in me mightily.