James 1:2-4 NIV
Consider it pure joy, my brothers and sisters, whenever you face trials of many kinds,  because you know that the testing of your faith produces perseverance.  Let perseverance finish its work so that you may be mature and complete, not lacking anything.
Hebrews 3:14 NIV
We have come to share in Christ, if indeed we hold our original conviction firmly to the very end.
Philippians 1:6 NIV
being confident of this, that he who began a good work in you will carry it on to completion until the day of Christ Jesus.