'Certain' in the Bible

Be sure to keep a distance of about 2,000 cubits between you and it. Don't come near it, so you can be certain where you're going, since you haven't passed this way before."

know for certain that the LORD your God will not continue to drive out these nations ahead of you. Instead, they will be a snare and a trap for you, a whip to your backs, and thorns in your eyes, until you perish from this good land that the LORD your God has given you.