We just learned the Fifth Commandment about not killing.
The sixth commandment that God gave to Moses is:
Thou shalt not commit adultery.
This means that married people need to love and be faithful to each other.
(from: wikisource - Luther's Small Catechism)
![sixth commandment](https://upload.wikimedia.org/wikipedia/commons/thumb/8/82/Nathan_and_David.jpg/456px-Nathan_and_David.jpg)
(from: wikipedia - thou shalt not commit adultery)