The following is from thewestminsterstandard.org:
Q. 46. What is required in the first commandment?
A. The first commandment requireth us to know and acknowledge God to be the only true God, and our God, and to worship and glorify him accordingly.
Q. 47. What is forbidden in the first commandment?
A. The first commandment forbiddeth the denying, or not worshipping and glorifying, the true God as God, and our God; and the giving of that worship and glory to any other, which is due to him alone.
Q. 48. What are we specially taught by these words, before me,” in the first commandment?
A. These words, before me,” in the first commandment teach us, that God, who seeth all things, taketh notice of, and is much displeased with, the sin of having any other God.
Q. 49. Which is the second commandment?
A. The second commandment is, Thou shalt not make unto thee any graven image, or any likeness of anything that is in heaven above, or that is in the earth beneath, or that is in the water under the earth; thou shalt not bow down thyself to them, nor serve them; for I the Lord thy God am a jealous God, visiting the iniquity of the fathers upon the children unto the third and fourth generation of them that hate me: and showing mercy unto thousands of them that love me, and keep my commandments.
Q. 50. 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.
Recommended sermon: The Westminster Assembly, by Dr. Sinclair B. Ferguson