Proverbs 27:5-6 says,
5 Open rebuke is better
Than love carefully concealed.
6 Faithful are the wounds of a friend,
But the kisses of an enemy are deceitful.
It is hard to think that to be a good friend you might have to wound your friend. However, Scripture teaches that a true friend will tell us the truth even when it hurts. This is easy to say but hard to practice.
In fact, God's Word tell us the one who flatters us is laying a trap....
A man who flatters his neighbor
Spreads a net for his feet. (Proverbs 29:5)
However, when we are called upon to speak the truth to our friend we should always do so out of a heart of love. We must be careful when we are candid to be forthright for the right reason. It is important to be led by the Spirit. Timing is crucial and only the Holy Spirit can lead you to the right time and the right place for the right reason.
28 The heart of the righteous studies how to answer,
But the mouth of the wicked pours forth evil.