"Whosoever hateth his brother is a murderer: and ye know that no murderer hath eternal life abiding in him." - 1 John 3:15
The Apostle John gave us a litmus test for telling if a person is truly saved in the above verse. If we do not love our brethren (speaking of fellow Christians), then we are the offspring of the Devil (Jn. 8:44). However, we are not supposed to just show love to other Christians, but love to everyone. If you are unsure how the Bible defines love, please see this lesson.
God made all of us in His image (Gen. 1:26). When we show hate, we are hating what God created. God, contrarily, "commendeth His love toward us, in that, while we were yet sinners, Christ died for us" (Rom. 5:8).
Throughout the Old Testament, God made it clear the only way to fulfill the Law was by loving Him and our fellowman more than we love ourselves (Matt. 22:36-40). Matthew chapter five described the Kingdom of Heaven in great detail which gives us great insight into God's character. Since God is light (1 Jn. 1:5) and love (1 Jn. 4:8) we know that in Him is no darkness and that His thoughts are always good.
You must understand that in God's eyes, murder is not simply the act of wrongfully taking a life (Ex. 21:12-17). Murder can also be unjust anger towards a person (Matt. 5:21-22). The Apostle John echoed this sentiment when he linked hate with murder (1 Jn. 3:15).
The reason that the Apostle Paul listed this sin separately is for the same reason that he listed fornication and adultery separately. Hate and murder are tied together, but under God's judgment, they are separate sins because He judges our motives as well (Jer. 17:10). As you have seen throughout this series, no sin acts alone. Sin builds upon sin and the only cure for sin is the love of Christ (Rom. 5:8-9).
Murder is the end result of hatred. Hatred towards someone will eventually come out through slander, physical assault, or other heinous acts. The greatest example of murder in the Bible is the story of Jesus Christ.
Jesus lived for 33.5 years and did not sin one time (1 Peter 2:22). Instead of being accepted as the Messiah, he was rejected. He was slandered and falsely accused of crimes He did not commit (Luke 23:2,5). He was arrested and assaulted, and finally, murdered on the cross.
If you have not accepted His free gift of salvation, you will stand before the Great White Throne Judgment (Rev. 20:11-15) where you will be tried for murder (among other sins). Jesus said, "if the world hate you, ye know that it hated Me before it hated you" (Jh. 15:18). The world hated Jesus and crucified Him (Jn. 3:19).
Next work of the flesh: drunkenness