" And the Lord said to Cain, “Why are you so angry? And why do you look annoyed? If you do well [believing Me and doing what is acceptable and pleasing to Me], will you not be accepted? And if you do not do well [but ignore My instruction], sin crouches at your door; its desire is for you [to overpower you], but you must master it." (Gen 4:6-7) Sin lies at the foot of every disobedience. When we obey God and His word, we live in righteousness; but when we step outside His will, His word, His purpose - the only thing lying out there is sin and a life of misery..
The story of the first two brothers, Cain and Abel is a tragedy. A story that ended in misery, in tears, in violence, in heartbreak, in disappointment - all because of one man's disobedience to the word of God. Cain failed to follow the instructions of God. He stepped outside the boundaries of obedience - and just as God rightly warned - what he met was sin crouching, hiding, laying wait at the door.
How often have we found ourselves in this kind of situation - a situation where we have to make the hard choice between obedience and disobedience. At some point in our lives, it seems so much easier to disobey, so much safer to move by sight instead of faith, so much easier to cross that boundaries and embrace whatever lies behind those doors. But God is saying "Don't do that, because you are going to regret it"
Stay within the borders. Stay in line. Stay in faith. Keep obeying God.
"But you must remain faithful to the things you have been taught. You know they are true, for you know you can trust those who taught you." (2 Tim 3:14. NLT)