Martin Collins, focusing upon Hebrews 11:4, affirms that Abel gave a more acceptable offering than Cain because the animal to be sacrificed in faith represented a substitutionary sacrifice, symbolic of the perfect sacrifice of Christ, the only payment through which our debt can be paid in full. It is useless for the sinner to bring anything of his own to pay the debt; we are obligated to trust in faith as Abel had demonstrated. In Abel‚s faith there was a living faith which resulted in obedience; in Cain‚s there was not.