Albert Barnes Commentary Psalms 54:4

"Behold, God is my helper: The Lord is of them that uphold my soul." — Psalms 54:4 (ASV)

Behold, God is mine helper - That is, God alone can aid me in these circumstances, and to him I confidently look.

The Lord is with them that uphold my soul - My friends; those who have rallied around me to defend me; those who comfort me by their presence; those who sustain me in my cause, and who keep me from sinking under the burden of my accumulated troubles.