Enmity is a state of opposition; deep-rooted hatred; hostility. Sometimes it is a cold and decidedly unfriendly disposition, constant and unrelenting; often in marriage referred to as "irreconcilable differences". It is at the heart of every prejudice of social class, racism and religious persecution, of ethnic cleansing and class warfare.
The Bible contains several references to enmity or hate.
In Genesis 3:15, "I will put enmity (ebhah) between thee and the woman, and between thy seed and her seed."
In Numbers 35:21-22, the absence of enmity on the part of the man-slayer modifies the judgment to be passed on him.
In the New Testament "enmity" is the translation of echthra.
In Luke 23:12 "Herod and Pilate became friends with each other that very day, for before this they had been at enmity with each other."
James 4:4 says, "Do you not know that friendship with the world is enmity (echthra) with God? Therefore whoever wishes to be a friend of the world makes himself an enemy of God."
"The mind that is set on the flesh is hostile (echthra) to God; it does not submit to God's law, indeed it cannot" (Romans 8:7).
"Do not love the world or the things in the world. If any one loves the world, love for the Father is not in him. For all that is in the world, the lust of the flesh and the lust of the eyes and pride of life, is not of the Father but is of the world." (1 John 2:15-16).
By the abrogation of the Mosaic institutes the "enmity" between Jew and Gentile is removed. Christ is said to have "abolished in his flesh the enmity," and by His cross to have "slain the enmity," that is, the opposition between Jew and Gentile. They are reconciled, creating in himself "one new man in place of the two, so making peace...thereby bringing the hostility (echthra) to an end." (Ephesians 2:14-16).
See external link Enmity (biblehub.com)