The history of the Old Testament reveals that idolatry was a very prevalent sin, not only among the heathen but also among the people of God. God made it very plain that He did not intend for it to be that way. In giving the Ten Commandments God said: "Thou shalt have no other gods before me. Thou shalt not make unto thee any graven image, nor any likeness of anything that is in heaven above, nor that is in the earth beneath, or that is in the water under the earth; thou shalt not bow down thyself unto them, nor serve them, for I Jehovah thy God am a jealous God, visiting the iniquity of the fathers upon the children, upon the third and fourth generation of them that hate me, and showing loving kindness unto thousands of them that love me and keep my commandments" (Exodus 20:3-6).
Despite this plain command of God, the history of the Old Testament reveals how the people of God wandered off into idolatry time after time. They were severely punished and would return to God, only to wander into idolatry again.
Finally, God, as punishment for their idolatry, sent them into slavery. The two tribes returned and small remnants of the other tribes. They learned their lesson. They were cured of their idol worship, and though they still have errors, the Jewish people do not worship idols.
They had learned that the best defense is an offense. After their return from captivity the Old Testament Scriptures were translated from the Hebrew into Greek. What English is today in the literary world, Greek was in that day. Through reading of the Bible there were many people in the world who were no longer idolaters when Jesus came. They had not embraced the Jewish faith but they did believe in the God whom the Old Testament reveals. Cornelius, in Acts 10, is an example. In the world of today wherever faith in the Bible goes, idolatry ceases.
The Old Testament reveals there is one God. The New Testament makes that truth even plainer.
Just as the Bible reveals one God, it reveals that there is one church. In fact it is explicit in teaching that sobering fact. There is no place in the plan of God for more than one God and there is no place for more than one church. The church was in the mind of God from eternity: "to the intent that now unto the principalities and powers in the heavenly places might be made known through the church the manifold wisdom of God, according to the eternal purpose which he purposed through Jesus Christ our Lord" (Ephesians 3:10,11).
Two truths are evident from this passage: that the manifold wisdom of God was to be made known through the church and that the whole truth, and nothing but the truth, is to be made known through the church. The work of the church was not an afterthought in the mind of God but it was His eternal purpose.
In the plan of God, the church was not to belong to one nation but to all the nations. This is how the Holy Spirit through Isaiah described the coming church: "And it shall come to pass in the latter days, that the mountain of Jehovah's house shall be established on the top of the mountains, and shall be exalted above the hills, and all nations shall flow unto it" (Isaiah 2:2). The Holy Spirit informs us that the house of God is the church of the living God (I Timothy 3:15). In plain language God said He would establish one church for all nations and Paul told us in Ephesians 3:10,11 that it was established for all time. He says further: "Now unto Him that is able to do exceeding abundantly above all that we ask or think, according to the power that worketh in us, unto Him be the glory in the church and in Christ Jesus unto all generations for ever and ever" (Ephesians 3:20,21).