Colossians 1:22-23: He has reconciled you in His fleshly body . . . if you continue in faith firmly established and steadfast.
Calvin once said the way you begin the Christian life isn’t very important. The big issue is not how you got started. The big issue is whether you persevere to the end. Calvin got this from Paul: We are reconciled if we continue in faith to the end.
This doesn’t mean we save ourselves. We’re saved as we keep trusting God to save us, as we trust the Spirit of Jesus to present us to the Father holy and blameless.
Even our persevering trust is a gift from God. God doesn’t get us started and leave us to ourselves. The Spirit continually renews our faith, not least at this table. Every week the Father reiterates His promise and reaffirms His determination to save.
Each week, God offers the gifts of God to the people of God: Here is the body of Christ, given for you; this cup is the new covenant, shed for you and for many for the remission of sins.
Your job is to believe Him. Take and continue in faith established and steadfast. Take and trust.