If you say someone has a 'discerning palate,' you are suggesting that they are able to rightly judge which foods are good (high quality, delicious, well made, etc.) and which are not. A discerning friend would be able to articulate insight and understanding as you tell them about a difficulty with which you are struggling. A discerning art critic can discriminate - see the distinct differences - between an original and a repoduction.
Followers of Jesus seek to do all of these things in their lives: judge what is good and what is not, bring God's insight and understanding to bear on the questions they face in life, and see the distinct differences between what is of God and what is not of God. But faithful discernment is a difficult task for even the most mature Christ followers. As we seek to live a life Designed by God, how can grow in our ability to discern what God would have us do, where God would have us go, and what God would have us think and pray?