Exodus 20:3-4 includes the ideas that God is the only god and I should have no images of gods. Depending on how one counts it is the First or The First and Second Commandments.
Thou shalt not have strange Gods before me. Thou shalt not make to thyself a graven thing, nor the likeness of anything that is in heaven above, or in the earth beneath, nor of those things that are in the waters under the earth. (Exodus 20:3-4)
So we worship only God like Luke said.
It is written, "The Lord thy God shalt thou worship, and him only shalt thou serve." (Luke 4:8)
Two worship God, I may use acts of faith, hope, and charity, and by praying to Him.
Faith means I that should learn about The Bible and Christian traditions. I should believe in The Bible and the traditions, and I should say that I am a Christian at appropriate times like Matthew said.
Therefore, everyone who acknowledges me before men, I also will acknowledge him before my Father in heaven. (Matthew 10:32)
Hope means that I should trust that God will give me eternal life, and that he will show me how to get there. Like Paul said to Titus.
Paul, a servant of God and apostle of Jesus Christ, in accordance with the faith of God's elect and the full knowledge of the truth which is according to piety, in the hope of life everlasting which God, who does not lie, promised before the ages began. (Titus 1:1-2)
Charity means that I should love God, and I should love my neighbor as myself like when a doctor of the law asked Jesus, "Master, which is the great commandment in the Law?"
Jesus said to him, 'Thou shalt love the Lord thy God with thy whole heart, and with thy whole soul, and with thy whole mind.' This is the greatest and the first commandment. And the second is like it, 'Thou shalt love thy neighbor as thyself.' On these two commandments depend the whole Law and the Prophets." (Matthew 22:35-40)
I should make frequent acts of faith. For example I should pray for strong faith, which seems like it should be easier than some things on the list. I should study my religion. I gotta admit that I did a rather poor job of that the first time around. I should live a good life, like for example, I should not associate with enemies of the Church. I should do good reading, like for example, I should not read books that oppose the Church. I suppose that means Richard Dawkins. He must be one of the wolves that Paul mentions in Acts.
I know that after my departure fierce wolves will get in among you, and will not spare the flock. And from among your own selves men will arise speaking perverse things, to draw away the disciples after them. (Acts 20:29-30)
Or enemies of the church could include my Persian cutie, who I met last year on September 11. The teacher introduced him as being from Iran. I said something rude like, “After school let’s go pray at a victory mosque.” He laughed, and I thought, “Wow, he has a sense of humor.” And I gave him my phone number. He never called, so I invited him to a church hay ride. We had tons of fun. I even forgot that he’s a Muslim.
I had no idea that the first commandment is so cowabunga complicated, and even worse, I should have learned all this already.
Also seems to me, now that I'm thinking about it, the First Commandment could have a more practical face