When David says "you are the lifter of my head" what does he mean? Does he mean that God helps him to maintain his courage? Or does he mean that he will be successful?
Barnes' Notes on the Bible says "encourage":
And the lifter up of my head - The head, in time of trouble and sorrow is naturally bowed down, as if overpowered with the weight of affliction. See Psa_35:14 : “I bowed down heavily as one that mourneth for his mother;” Psa_38:6 : “I am bowed down greatly; I go mourning all the day.” Compare Psa_42:5; Psa_44:25; Psa_57:6; Joh_19:30. To lift up the head, therefore, or to raise one up, is to relieve his distresses, or to take away his troubles. Such a helper, David says, he had always found God to be, and he looks to him as one who is able to help him still. That is, he feels that God can so entirely take away his present griefs as to reinstate him in his former happy and honorable condition.
While The Cambridge Bible for Schools and Colleges has "restoration":
the lifter up of mine head] A general truth. David is still confident that as Jehovah raised him from low estate to royal dignity, and brought him up from depths of trouble in times past, He can even now save him and restore him to the throne. Cp. 2Sa_15:25.
Which is it? Or both? Or something else?