On Mt. Sinai when God gave the Ten Commandments to man, he made it plain that nothing was to come before him.
"And God spake all these words, saying, I am the Lord thy God, which have brought thee out of the land of Egypt, out of the house of bondage. Thou shalt have no other gods before me. 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;" (Ex. 20:1 -- Ex. 20:5).
As one studies the Old Testament, they see that God’s people did not keep this commandment. Time and time again they were warned by the messengers of God to put away idols and turn back to God, but they refused. This led to their eventual downfall, as God allowed foreign nations to overtake them. God had told them this would happen if they did not keep his commands, but they failed to heed his warnings.
God still demands that he be put first in the hearts of men today, in everything. His desire is for all men to come to him through his Son. "Jesus saith unto him, I am the way, the truth, and the life: no man cometh unto the Father, but by me" (John 14:6).
He will not tolerate those who would try to come to him by a different way. Men down through history have tried to come up with their way of getting to God. Even when Christ was upon the earth, men were teaching things contrary to God’s commandments. "But in vain they do worship me, teaching for doctrines the commandments of men" (Matt. 15:9).
Man was not and is not capable of coming up with a "saving plan" on his own. Jeremiah the prophet recorded these words by inspiration, "O Lord, I know that the way of man is not in himself: it is not in man that walketh to direct his steps" (Jer. 10:23).
God’s plan for man’s salvation has been in the mind of God from the beginning, and he has marvelously and wondrously worked out his plan for man. Jesus said, "Not everyone that saith unto me, Lord, Lord, shall enter into the kingdom of heaven; but he that doeth the will of my Father which is in heaven. Many will say to me in that day, Lord, Lord, have we not prophesied in thy name? And in thy name have cast out devils? And in thy name done many wonderful works? And then will I profess unto them, I never knew you: depart from me, ye that work iniquity" (Matt. 7:21 -- Matt. 7:23).
God’s plan is seen in how those in the first century obeyed the gospel. They believed in Christ as God’s Son, they willingly repented of their sins, confessed the name of Christ before men and were baptized for the remission of their sins.
Now just as always God wants to be first in the lives of men. His desire is that all will obey him and seek to put him first in their lives.