Verses with the word admonish in the New Testament (3 verses):

Romans 15:14
And I myself also am persuaded of you, my brethren, that ye also are full of goodness, filled with all knowledge, able also to admonish one another.

1 Thessalonians 5:12
And we beseech you, brethren, to know them which labour among you, and are over you in the Lord, and admonish you;

2 Thessalonians 3:15
Yet count him not as an enemy, but admonish him as a brother.