Heidelberg Catechism - Lord's Day 40

105. Q . What is God’s will for you in the sixth commandment?
        A. I am not to belittle, hate, insult, or kill my neighbor— not by my thoughts, my words, my look or gesture, and certainly not by actual deeds—
and I am not to be party to this in others; rather, I am to put away all desire for revenge. I am not to harm or recklessly endanger myself either. Prevention of murder is also why government is armed with the sword.

106. Q . Does this commandment refer only to murder?
        A. By forbidding murder God teaches us that he hates the root of murder: envy, hatred, anger, vindictiveness. In God’s sight all such are disguised forms of murder.

107. Q . Is it enough then that we do not murder our neighbor in any such way?
        A. No.
By condemning envy, hatred, and anger God wants us to love our neighbors as ourselves, to be patient, peace-loving, gentle, merciful, and friendly toward them, to protect them from harm as much as we can, and to do good even to our enemies.