This Psalm has a great back story. While on the run from King Saul, David stopped by Israel's enemy, King Achish of Gath in I Samuel 21. To avoid being killed as a threat, David pretended to be insane. Achish let him go. In response to the Lord's favor and deliverance from a time of trouble, David composed this psalm.
It contains the classic phrase: "O taste and see that the Lord is good" (vs. 8). I will always remember this verse being preached during chapel at Ashland Seminary by Dr. Jerry Flora. He passed out Werther's candies for us to let slowly dissolve in our mouths while he preached about the goodness of the Lord. (Remembering it 20 years later, it must have made an impression!) For those not sure about whether they should trust the Lord or not, let us encourage them to "Taste and See that the Lord is Good!"
There is also a wonderful formulation in this psalm concerning the way God treats people. "The eyes of the Lord are on the righteous, and his ears are open to their cry" (vs. 15) Contrast this with: "The face of the Lord is against evildoers, to cut off the remembrance of them from the earth" (vs. 16).
From David's own experience, he is able to encourage and teach us to fear the Lord and put our trust in Him!