'Holy to the Lord' in the Bible

For there were still a number of the people there who had not made themselves holy: so the Levites had to put Passover lambs to death for those who were not clean, to make them holy to the Lord.

And he said to the Levites, the teachers of all Israel, who were holy to the Lord, See, the holy ark is in the house which Solomon, the son of David, king of Israel, made; it will no longer have to be transported on your backs: now be the servants of the Lord your God and his people Israel,