There is one lawgiver; one absolute, supreme, universal and spiritual Lawgiver, and who can simply and directly bind men's consciences, and make laws for their souls, Proverbs 8:15,16 Isa 33:22 Acts 4:19. By this he intimates, that they did invade God's right, who took upon them a legislative power in prescribing to other men's consciences, and making their own will the rule of the others duty. Who is able to save and to destroy, both temporally and eternally, Deuteronomy 32:39 1 Samuel 2:6 Isaiah 43:13; whereas other lawgivers cannot save or destroy men's souls, nor so much as their lives, without God's concurrence. Who art thou; what a sorry creature, a man, a worm, that thou shouldst lift up thyself into God's place, and make thyself a judge of one not subject to thee! That judgest another; the servant of another Master, Romans 14:4. It is a fond thing for thee to take upon thee the power of a judge, when thou hast no power of saving or destroying, rewarding or punishing.
Related Commentaries of James 4:12
James 4:12
12 There is one lawgiver, who is able to save and to destroy: who art thou that judgest another?