"Then God spoke all these words: I am the Lord your God, who brought you out of the land of Egypt, out of the place of slavery. Do not have other gods besides Me." - Exodus 20:1-2

The First Commandment.

Not the greatest one ... the First one. You will find the greatest one in Deuteronomy 6:5 - "Love the Lord your God with all your heart, with all your soul, and with all your strength." In fact, Deuteronomy 5 exactly repeats the commandments in Exodus 20, and then adds additional ordinances and statutes - Deuteronomy is Moses reminding the Israelites of the Law they received so many years ago at Horeb, just before they are getting ready to cross into the Promised Land. Exodus has the account of the actual law giving event that happened 40 years ago.

These were the first Words out of the mouth of God to the nation Israel. Not in letter or tablet or scroll format - but actual words they HEARD. The text says God SPOKE all these words. It is confirmed. "The Lord spoke to you face to face from the fire on the mountain." - Deut 5:4, "Has a people heard God's voice speaking from the fire as you have, and lived?" - Deut 4:33 "He let you hear His voice from heaven to instruct you."- Deut 4:36 There is no doubt here - the people heard God speak with their own ears!

He gave them His Top Ten list and then mercifully paused - knowing the effect it was having on them.

Moses recounts it - "The Lord spoke these commands in a loud voice to your entire assembly from the fire, cloud, and thick darkness on the mountain; He added nothing more. He wrote them on two stone tablets and gave them to me." - Deut 5:22 He goes on in the same place to describe the people's response. They actually begged Moses to be their representative and said we can't handle God speaking to us, you go and listen to Him and tell us what He says, because it's freaking us out !!!! :-) This was a unique event in the history of mankind - the public inauguration of God as the leader of His chosen people - and it was broadcast to all of them.
I don't think it was the volume of His voice that scared them. I think it was the purity of it, the absolute perfection of it, the conviction it brought to them of their sinfulness in violating even these ten things that drove them to their knees in absolute terror. I remember one day meditating on the absolute perfection of One who not only sets the moral standard for all the host of Heaven but all of whose actions and judgements are perfect in their sight for all eternity and it drove me to lie prostrate and trembling flat on my face knowing what a sinful worm I was in comparison to that standard of purity.

Yet, the first words out of His mouth are those of Grace and Salvation. He says He is the one who brings us out of the place of slavery and bondage! His first words of identity to His people are that of Savior! Not Creator - as is His right - but Savior, Redeemer - as One who has paid the price for us to release us from the bondage and captivity of sin. Oh wonderful God!!

How then can we turn from trusting Him who created and redeemed us to trusting and relying on the work of our hands, or worshipping things we have created, or worshipping any other spiritual being ? After all, that is what the definition of a god is - whatever/whoever you trust and give your time, resources and affection to in the hopes that it/he will help you when you need it. Money, Power, Fame, Friends, Family, Spirits, Horoscopes/Astrology? Sin will cause us to turn to these things and rely on them, and give glory and credit to them for our continued well being and prosperity.... hence the First commandment is given to remind us...

There is only One who saves us and is worthy of worship and trust. Do not incur His wrath by turning from Him who purchased you with His own blood to worship gods that have no power to do anything for or to you. The First commandment should not even be necessary!!! It is born out of the wisdom of God knowing the power of sin that makes us rely on our arms of flesh and our propensity to worship that which we can see.
There is no God like Him in all the universe. There should be no God to compete with Him in our hearts. Be ready to receive both prosperity and difficulties from His hand and don't stumble when He seems to have hidden His face from you. Trust that all things will work to your ultimate good even though it may be difficult for a season.

"Trust in the Lord with all your heart, And lean not on your own understanding; In all your ways acknowledge Him, And He shall direct your paths.Do not be wise in your own eyes; Fear the Lord and depart from evil. It will be health to your flesh, And strength to your bones. Honor the Lord with your possessions, And with the firstfruits of all your increase; So your barns will be filled with plenty, And your vats will overflow with new wine. My son, do not despise the chastening of the Lord, Nor detest His correction; For whom the Lord loves He corrects, Just as a father the son in whom he delights. Happy is the man who finds wisdom, And the man who gains understanding; For her proceeds are better than the profits of silver, And her gain than fine gold. She is more precious than rubies, And all the things you may desire cannot compare with her. Length of days is in her right hand, In her left hand riches and honor. Her ways are ways of pleasantness, And all her paths are peace." - Proverbs 3:5-17