Q: What is required in the second commandment?
A: The second commandment requireth the receiving, observing, and keeping pure and entire, all such religious worship and ordinances as God hath appointed in his word.

Deuteronomy 12:32. What thing soever I command you, observe to do it: thou shalt not add thereto, nor diminish from it.
Deuteronomy 32:46. And he said unto them, Set your hearts unto all the words which I testify among you this day, which ye shall command your children to observe to do, all the words of this law.
Matthew 28:20. Teaching them to observe all things whatsoever I have commanded you: and, lo, I am with you alway, evenunto the end of the world. Amen.

Westminster Project - See Matthew Henry's Scripture Catechism based on the WSC