What does Genesis 4:6 mean?

Already in Genesis we have seen that when God interacts with people, He sometimes asks questions. Obviously, God knows the answers to His questions. Rather, God asks in the same way a human father might question a child. He appears to want to engage them in conversation, to prompt them to think about their choices. God wants to hear them express the state of their own hearts. Fatherly questions are an opportunity for the child to be open, honest, and trusting of their parent.

Here God asks Cain to think about, explain, and express why he feels so angry. God's question not only seeks Cain's response, but hints that there is no good reason for Cain to feel this way. God's rejection of Cain and his offering has caused his face to fall, and God wants Cain to understand and own the reasons for His anger. However, as the next verse shows, this is not a necessary reaction. God is willing to accept Cain if Cain chooses a better path.

God still calls for His people to express themselves to Him in prayer, even in seasons of rebellion and hurt. Some of the Psalms model those kinds of honest, hard prayers for us.