There is much good advice in Hebrews 12, including verse 14:
Pursue peace with all people, and holiness, without which no one will see the Lord (NKJV).
Most people who bring up the idea that we need to be “holy” have no way to talk about it but to give us rules to follow that they would have us believe will make us holy if we can live by them. That distortion of the idea reverses cause and effect between being holy and being well behaved. Good behavior is actually a result of being properly holy.
Relative words are “holy,” which means “set apart,” “sanctified,” which is a transliterated foreign word meaning “made holy,” “saints,” meaning “holy people,” and “unto.”
“Unto” is related because just being “set apart” is an incomplete idea without the detail of what, or whom, the holy thing or person has been set apart to. Yahweh instructed Aaron and his sons to write, “HOLY TO YAHWEH” on a plate of gold and fasten it to the front of their turbans (Exodus 28:35). That complete phrase meant, “MINE.”
Temple prostitutes were called holy people, because they had been set apart for ritual sex.
A good checkup is to frequently examine areas of our lives and properties and valuables, to test them regarding what they are set apart to. The question we need to always answer well is not “How holy are we?” but “To what are we holy?”