What are we commanded by the First Commandment?

By the First Commandment we are commanded to offer to God alone the supreme worship that is due Him.

It is written, "The Lord thy God shalt thou worship, and him only shalt thou serve."  (Luke 4:8)

Saint Jerome

We worship God by acts of faith, hope, and charity, and by adoring Him and praying to Him

Faith obliges us: first, to make efforts to find out what God has revealed; second, to believe firmly what God has revealed; third, to profess our faith openly whenever necessary.

Therefore, everyone who acknowledges me before men, I also will acknowledge him before my Father in heaven. (Matthew 10:32)

Hope obliges us to trust firmly that God will give us eternal life and the means to obtain it.

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 obliges us to love God above all things because He is infinitely good, and to love our neighbor as ourselves for the love of God.

And one of them, a doctor of the Law, putting him to the test, asked him, "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)

A Catholic can best safeguard his faith by making frequent acts of faith, by praying for a strong faith, by studying his religion very earnestly, by living a good life, by good reading, by refusing to associate with the enemies of the Church, and by not reading books and papers opposed to the Church and her teaching.

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 rise speaking perverse things, to draw away the disciples after them.  (Acts 20:29-30)

A Catholic sins against faith by apostasy, heresy, indifferentism, and by taking part in non-Catholic worship.

A Catholic sins against faith by taking part in non-Catholic worship when he intends to identify himself with a religion he knows is defective.

This is why I was born, and why I have come into the world, to bear witness to the truth.  Everyone who is of the truth hears my voice.  (John 18:37)

The sins against hope are presumption and despair.

A person sins by presumption when he trusts that he can be saved by his own efforts without God's help, or by God's help without his own efforts.

Nay I do not even judge my own self.   For I have nothing on my conscience, yet I am not thereby justified.  (I Corinthians 4:4)

A person sins by despair when he deliberately refuses to trust that God will give him the necessary help to save his soul.

May no temptation take hold of you but such as man is equal to.  God is faithful and will not permit you to be tempted beyond your strength, but with the temptation will also give you a way out that you may be able to bear it.  (I Corinthians 10:13)

The chief sins against charity are hatred of God and of our neighbor, envy, sloth, and scandal.

Charity does not envy.  (I Corinthians 13:4)

Besides the sins against faith, hope, and charity, the first commandment forbids also superstition and sacrilege.

A person sins by superstition when he attributes to a creature a power that belongs to God alone, as when he makes use of charms or spells, believes in dreams or fortune-telling, or goes to spiritists.

Neither let there be found among you any one that ... consulteth soothsayers, or observeth dreams and omens.  Neither let there be any wizard, nor charmer.  (Deuteronomy 19:10-11

Saint Thérèse

A person sins by sacrilege when he mistreats sacred persons, places, or things.

They have set thy sanctuary ablaze, they have profaned the dwelling of thy name on the earth.  (Psalm 73:7)

The first commandment does not forbid us to honor the saints in heaven, provided we do not give them the honor that belongs to God alone.

For, behold, henceforth all generations shall call me blessed.  (Luke 1:48)

We honor the saints in heaven because they practiced great virtue when they were on earth, and because in honoring those who are the chosen friends of God we honor God Himself.

We can honor the saints: first, by imitating their holy lives; second, by praying to them; third, by showing respect to their relics and images.

Brethren, be imitators of me, and mark those who walk after the pattern you have in us.  (Philippians 3:17)

When we pray to the saints we ask them to offer their prayers to God for us.

We know that the saints will pray for us because they are with God and have great love for us.

We honor relics because they are the bodies of the saints or objects connected with the saints or with Our Lord.

The first commandment forbids the making or the use of statues and pictures only when they promote false worship.

Thou salt 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)

It is right to show respect to the statues and pictures of Christ and of the saints, just as it is right to show respect to the images of those whom we honor or love on earth.

We honor Christ and the saints when we pray before the crucifix, relics, and sacred images because we honor the persons they represent; we adore Christ and venerate the saints.

We do not pray to the crucifix or to the images and relics of the saints, but to the persons they represent.