Ahab showed no interest in hearing the truth. His fellow king Jehoshaphat had a reputation as a good king, a true follower of the LORD. As disciples of Jesus, we learn to HEAR and SPEAK the truth in love.
If we're ever going to be in a place to judge others (help them with the speck in their eye), we need to first submit ourselves to judgment (deal with the plank in our own eye).
Christians believe that God knows everything. If this is so, why pray? Taking Jesus, the Son of God incarnate, as our example, we learn that what we call a "relationship with God" is constituted by prayer.