2 Timothy 2:22 (WEB)
Flee from youthful lusts; but pursue righteousness, faith, love, and peace with those who call on the Lord out of a pure heart.
Catechism · 1
“"Pure in heart" refers to those who have attuned their intellects and wills to the demands of God's holiness, chiefly in three areas: charity;” — Catechism footnote: Cf. 1 Tim 4:3-9; 2 Tim 2:22.