John Gill Commentary Psalms 109:16

"Because he remembered not to show kindness, But persecuted the poor and needy man, And the broken in heart, to slay [them]." — Psalms 109:16 (ASV)

Because that he remembered not to show mercy
As Judas did not; neither to the poor, whom he cared not for, (John 12:6) nor to Christ, whom he betrayed with a kiss to his enemies: nor had these words of Christ any effect upon him, to move his pity and compassion, "Friend, wherefore are you come?" (Matthew 26:49Matthew 26:50) nor did the Jews show mercy to him: they were a merciless and hardhearted people; though mercy was one of the weightier matters of the law, this they omitted, (Matthew 23:23) , their want of compassion may be observed in the priest and Levite passing by the man wounded by thieves, (Luke 10:30–32) . Nor did they show any mercy to Christ, when they smote and buffeted him; nor did it move their pity when Pilate brought him forth with a crown of thorns on his head, and in a miserable condition, saying, "Behold the man"; but they cried out, "Crucify him, crucify him"; and gave him gall for his meat, and vinegar to drink; and mocked him when in all his miseries and agonies.

But persecuted the poor and needy man ;
Christ, who became poor for our sakes, and stood in need of the ministration of others to him, (2 Corinthians 8:9) (Luke 8:3) and was poor in spirit, a man of sorrows, and acquainted with griefs; him Judas and the Jews persecuted to death, as follows:

that he might even slay the broken in heart ;
Christ, whose heart was broken with the reproach and cruel usage of men, (Psalms 69:20) , whose life the Jews sought to take away, and by means of Judas did.