'Fast' in the Bible

but Christ [was faithful] as a son over his house, whose house we are, if we hold fast to our confidence and the hope we can be proud of.

For we have become partners of Christ, if indeed we hold fast the beginning of [our] commitment steadfast until the end,

Therefore, [because we] have a great high priest who has gone through the heavens, Jesus the Son of God, let us hold fast to our confession.

in order that through two unchangeable things, in which [it is] impossible for God to lie, we who have taken refuge may have powerful encouragement to hold fast to the hope set before [us],

Let us hold fast to the confession of [our] hope without wavering, for the one who promised [is] faithful.