'Fast' in the Bible

but Christ was faithful as a Son over His house—whose house we are, if we hold fast our confidence and the boast of our hope firm until the end.

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

Therefore, since we have a great high priest who has passed through the heavens, Jesus the Son of God, let us hold fast our confession.

Let us hold fast the confession of our hope without wavering, for He who promised is faithful;