Selfishness is the root of all sin...

Due to selfishness being the root of all sin it in and of itself is sin because all it takes is a carnal mind to be at war (enmity) with God.

Because the carnal mind is enmity against God: for it is not subject to the law of God, neither indeed can be. Romans 8:7 Lucifer was selfish in desiring more for himself. He sought equality with his Creator. How art thou fallen from heaven, O Lucifer, son of the morning! how art thou cut down to the ground, which didst weaken the nations! [13] For thou hast said in thine heart, I will ascend into heaven, I will exalt my throne above the stars of God: I will sit also upon the mount of the congregation, in the sides of the north: [14] I will ascend above the heights of the clouds; I will be like the most High. [15] Yet thou shalt be brought down to hell, to the sides of the pit. Isaiah 14:12-15 Adam and Eve sinned out of selfishness. They also, like Lucifer, sought equality with their Creator. And the serpent said unto the woman, Ye shall not surely die: [5] For God doth know that in the day ye eat thereof, then your eyes shall be opened, and ye shall be as gods, knowing good and evil. [6] And when the woman saw that the tree was good for food, and that it was pleasant to the eyes, and a tree to be desired to make one wise, she took of the fruit thereof, and did eat, and gave also unto her husband with her; and he did eat. Genesis 3:4-6 God came in the flesh to demonstrate how we can shed selfishness and die to self. Jesus showed us how we can, and we really can..., humbly serve our Creator in life and death. Let this mind be in you, which was also in Christ Jesus: [6] Who, being in the form of God, thought it not robbery to be equal with God: [7] But made himself of no reputation, and took upon him the form of a servant, and was made in the likeness of men: [8] And being found in fashion as a man, he humbled himself, and became obedient unto death, even the death of the cross. Philippians 2:5-8 And whosoever of you will be the chiefest, shall be servant of all. [45] For even the Son of man came not to be ministered unto, but to minister, and to give his life a ransom for many. Mark 10:44-45 I am crucified with Christ: nevertheless I live; yet not I, but Christ liveth in me: and the life which I now live in the flesh I live by the faith of the Son of God, who loved me, and gave himself for me. Galatians 2:20 Then said Jesus unto his disciples, If any man will come after me, let him deny himself, and take up his cross, and follow me. [25] For whosoever will save his life shall lose it: and whosoever will lose his life for my sake shall find it. [26] For what is a man profited, if he shall gain the whole world, and lose his own soul? or what shall a man give in exchange for his soul? Matthew 16:24-26