'Firm' in the Bible

Therefore, we speak of you with pride among the churches of God for your steadfastness [your unflinching endurance, and patience] and your firm faith in the midst of all the persecution and [crushing] distress which you endure.

So then, brothers and sisters, stand firm and hold [tightly] to the traditions which you were taught, whether by word of mouth or by letter from us.

But the Lord is faithful, and He will strengthen you [setting you on a firm foundation] and will protect and guard you from the evil one.