For their Redeemer is mighty. The redeemer (goel) is the near kinsman, who had to avenge bloodshed, carry on the blood feud, or vindicate the cause of a relation otherwise unsupported (see Numbers 25:12, 19, 21; Le 25:25; Ruth 3:2, Ruth 3:9, Ruth 3:12).
God himself will be the orphans' Goel. This term is often applied to God; e.g. Job 19:25; Psalms 19:14; Jeremiah 50:34. He shall plead their cause with thee. He will, as it were, conduct their cause, try thee, convict thee of injustice, and pronounce thy condemnation (Proverbs 22:23).