Genesis 4:6

6 The LORD said to Kayin, "Why are you angry? Why has the expression of your face fallen?

Genesis 4:6 Meaning and Commentary

Genesis 4:6

And the Lord said unto Cain, why art thou wroth? and why is
thy countenance fallen?
&c.] Which was said not as being ignorant of his wrath and resentment, but to bring him to a conviction of his sin or sins, which were the cause of God's rejecting his sacrifice, and to repentance and amendment; and to show him that he had no cause to be displeased, either with him or his brother, for the different treatment of him and his offering; since the fault lay in himself, and he had none to blame but his own conduct, which for the future he should take care to regulate according to the divine will, and things would take a different turn.

Genesis 4:6 In-Context

4 Hevel also brought some of the firstborn of his flock and of the fat of it. The LORD respected Hevel and his offering,
5 but he didn't respect Kayin and his offering. Kayin was very angry, and the expression on his face fell.
6 The LORD said to Kayin, "Why are you angry? Why has the expression of your face fallen?
7 If you do well, will it not be lifted up? If you don't do well, sin crouches at the door. Its desire is for you, but you are to rule over it."
8 Kayin said to Hevel, his brother, "Let's go into the field." It happened, when they were in the field, that Kayin rose up against Hevel, his brother, and killed him.
The Hebrew Names Version is in the public domain.