'Continue' in the Bible

What shall we say then? Shall we continue in sin, that grace may abound?

See then the goodness and severity of God. Toward those who fell, severity; but toward you, goodness, if you continue in his goodness; otherwise you also will be cut off.

They also, if they don't continue in their unbelief, will be grafted in, for God is able to graft them in again.