'Assurance' in the Bible

For we have become partakers of Christ, if we hold fast the beginning of our assurance firm until the end,

And we desire that each one of you show the same diligence so as to realize the full assurance of hope until the end,

let us draw near with a sincere heart in full assurance of faith, having our hearts sprinkled clean from an evil conscience and our bodies washed with pure water.

Now faith is the assurance of things hoped for, the conviction of things not seen.