Hebrews 12:6-8

6because the Lord disciplines the one he loves, and he chastens everyone he accepts as his son.” Prov. 3:11,12 (see Septuagint) 7Endure hardship as discipline; God is treating you as his children. For what children are not disciplined by their father? 8If you are not disciplined—and everyone undergoes discipline—then you are not legitimate, not true sons and daughters at all.