John Gill Commentary Psalms 63:4

"So will I bless thee while I live: I will lift up my hands in thy name." — Psalms 63:4 (ASV)

Thus will I bless thee while I live
With his whole heart and soul, as he has sought after him, and as under a sense of his lovingkindness; and as he now praised him with his lips, so he determined to do as long as he had life and being; by proclaiming his blessedness, by ascribing blessing and honour to him, and by giving him the glory of all mercies temporal and spiritual;

I will lift up my hands in your name ;
not against his enemies, against those that fought against him, as Kimchi and Ben Melech interpret it, but unto God in heaven; and that not as a gesture used in swearing, but either in blessing, as Aben Ezra observes; so the high priest lifted up his hands when he blessed the people; or in prayer, or in both, so Jarchi's note is, to pray and to praise; (See Gill on Psalms 28:2). The Targum is, "in the name of your Word I will spread out my hands in prayer for the world to come;" that is, in the name of the Messiah, the essential Word, in whose name prayer is to be made, and whereby it becomes prevalent and successful; see (John 14:13John 14:14) (John 16:23John 16:24John 16:26) . This is a prayer gesture; (See Gill on Psalms 28:2).