John Gill Commentary Psalms 109:31

"For he will stand at the right hand of the needy, To save him from them that judge his soul." — Psalms 109:31 (ASV)

For he shall stand at the right hand of the poor
Of the Messiah, as in (Psalms 109:22) at whose right hand the Lord was, to guide and direct, help and assist, protect and defend, (Psalms 16:8) , or of his people, who are poor in every sense; but the Lord is on their side, and is a present help in time of trouble, (Psalms 46:1Psalms 46:5) .

To save him from those that condemn his soul :
the Messiah: from his judges, the high priest and Jewish sanhedrim, and Pilate the Roman governor, who condemned him to death; but he committed his spirit, or soul, to God, who received it, and raised his body from the dead; and would not suffer it to see corruption, as a testimony of his innocence: or the soul of the poor saints, which the Lord saves from the condemnation of sin, Satan, the law, and their own consciences, (Romans 8:1Romans 8:33Romans 8:34) .