How do we know that Abel's sacrifice was more acceptable to God?

Abel's sacrifice was accepted by God because it was offered with faith, as expressed in Hebrews 11:4 where it states, 'By faith Abel offered unto God a more excellent sacrifice than Cain.' Abel recognized the necessity of a blood sacrifice to atone for sin and understood that this acted as a type of Christ’s ultimate sacrifice. His faith indicated a divine revelation of God's provision for redemption, resulting in God's testimony that Abel was righteous. In contrast, Cain's offering lacked this faith and the acknowledgment of the need for atonement, showing a reliance on human effort rather than divine grace.