Proverbs 27:1-6

Praise and rebuke.
v.1-2 Let others praise you. Do not boast about tomorrow for you don't know what the day will bring forth (Lk 12:19-20, Jas 4:13-14). Turn to Christ today for this day could be your very last. Don't procrastinate until tomorrow what you can do today. Don't boast about yourself, let another praise you (2 Cor 10:18). Use your lips to praise and build up someone else, not to praise yourself.
v.3-4 A stone. A stone is heavy and sand is weighty, but the resentment (vexation) caused by a fools words and actions is even heavier. Wrath is cruel and anger is overwhelming (like a flood), but jealousy (envy) is even more dangerous.
v.5-6 Open rebuke. An open rebuke is better than hidden love (28:23). A rebuke allows one to consider the path he is walking on, while hidden love fails to communicate faults. The wounds of a friend are faithful and better than many kisses from an enemy. The kiss of Judas carried a traitorous venom. Rebukes are good and better than silent friendship.

Read Proverbs 27:1-6