Acts 20:31

So be on guard; and remember that for three years I ceased not to admonish you all, night and day, even with tears.

1 Thessalonians 5:14

And, brothers, we urge you to admonish the disorderly, comfort the faint-hearted, sustain the weak, lose patience with none.

Treasury of Scripture Knowledge

Summary

And what cause soever shall come to you of your brethren that dwell in their cities, between blood and blood, between law and commandment, statutes and judgments, ye shall even warn them that they trespass not against the LORD, and so wrath come upon you, and upon your brethren: this do, and ye shall not trespass.

Bible References

Warn them

Acts 20:31
So be on guard; and remember that for three years I ceased not to admonish you all, night and day, even with tears.
1 Thessalonians 5:14
And, brothers, we urge you to admonish the disorderly, comfort the faint-hearted, sustain the weak, lose patience with none.