'Firm' in the Bible

But he who stands firm in his heart (who is under no compulsion, but has control over his own will) and has decided in his heart to keep his own virgin, will do well.

Therefore let the one who thinks he stands firm [immune to temptation, being overconfident and self-righteous], take care that he does not fall [into sin and condemnation].

I praise and appreciate you because you remember me in everything and you firmly hold to the traditions [the substance of my instructions], just as I have passed them on to you.

So then, my beloved brethren, be firm, immovable, abounding always in the work of the Lord, knowing that your toil is not in vain in the Lord.

Be alert, stand firm in the faith, act like a man, be strong.