In Psalm 3:3 David says of God, “But you, O Lord, are a shield about me, my glory, and the lifter of my head.”
Dr. Sam Storms, of Enjoying God Ministries comments:
When people are shy or ashamed or unsure of themselves or insecure, they rarely look up or make eye-contact with you. David was probably having doubts about himself: about his worthiness to be king, about his abilities, about his manhood. God alone can give him (you) both reason and strength to walk with his (your) head up. This isn’t arrogance or presumption but humble assurance that God can do for us what we can’t do for ourselves. People often say: “I just can’t bear to look anyone in the face after this.” But God will make you able! See 1 Sam. 2:7-8; Ps. 27:4-6.