From the Heidelberg catechism:
Question 105. What does God require in the sixth commandment?
Answer: That neither in thoughts, nor words, nor gestures, much less in deeds, I dishonor, hate, wound, or kill my neighbor, by myself or by another: but that I lay aside all desire of revenge: also, that I hurt not myself, nor willfully expose myself to any danger. Wherefore also the magistrate is armed with the sword, to prevent murder.
Question 106. But this commandment seems only to speak of murder?
Answer: In forbidding murder, God teaches us, that he abhors the causes thereof, such as envy, hatred, anger, and desire of revenge; and that he accounts all these as murder.
Question 107. But is it enough that we do not kill any man in the manner mentioned above?
Answer: No: for when God forbids envy, hatred, and anger, he commands us to love our neighbor as ourselves; to show patience, peace, meekness, mercy, and all kindness, towards him, and prevent his hurt as much as in us lies; and that we do good, even to our enemies.
But he, desiring to justify himself, said to Jesus, “And who is my neighbor?” Jesus replied, “A man was going down from Jerusalem to Jericho, and he fell among robbers, who stripped him and beat him and departed, leaving him half dead. Now by chance a priest was going down that road, and when he saw him he passed by on the other side. So likewise a Levite, when he came to the place and saw him, passed by on the other side. But a Samaritan, as he journeyed, came to where he was, and when he saw him, he had compassion. He went to him and bound up his wounds, pouring on oil and wine. Then he set him on his own animal and brought him to an inn and took care of him. And the next day he took out two denarii and gave them to the innkeeper, saying, ‘Take care of him, and whatever more you spend, I will repay you when I come back.’ Which of these three, do you think, proved to be a neighbor to the man who fell among the robbers?” He said, “The one who showed him mercy.” And Jesus said to him, “You go, and do likewise.” (Luke 10:29-37 ESV)