sn The Letter to the Hebrews explains the difference between the brothers as one of faith—Abel by faith offered a better sacrifice. Cain’s offering as well as his reaction to God’s displeasure did not reflect faith. See further B. K. Waltke, “Cain and His Offering,” WTJ 48 (1986): 363–72.
tnHeb “and it was hot to Cain.” This Hebrew idiom means that Cain “burned” with anger.
tnHeb “And his face fell.” The idiom means that the inner anger is reflected in Cain’s facial expression. The fallen or downcast face expresses anger, dejection, or depression. Conversely, in Num 6 the high priestly blessing speaks of the Lord lifting up his face and giving peace.