“who will also confirm you to the end, that you may be blameless in the day of our Lord Jesus Christ. God is faithful, by whom you were called into the fellowship of His Son, Jesus Christ our Lord.” (1 Corinthians 1:8-9)
Who will confirm the believer till the day of Christ? A quick glance back to verse four reminds us of that answer. Paul had addressed his thanksgiving to God (vs.4a), the one who bestows grace (vs.4b). God is the one who calls believers into fellowship with His Son (vs.9b). And part of what makes that grace so amazing is that it is completely sustaining; it confirms believers till the end.