God has given his word to mankind. "God, who at sundry times and in divers manners spake in time past unto the fathers by the prophets, Hath in these last days spoken unto us by his Son, whom he hath appointed heir of all things, by whom also he made the worlds;" (Heb. 1;1, 2).
God spoke directly to the fathers in a time known as the "Patriarchal" or "father rule." God spoke to men such as Adam, Noah, Job, Abraham, etc., God directed them in the things they were to do and not do.
At Mount Sinai God gave to man his first written law, it was added to the promise God had made to Abraham because of the sins of the people (Galatians 3:19). That law (law of Moses) continued until the law of Christ took effect and it is under that law that man lives today.
Paul wrote, "But before faith came, we were kept under the law, shut up unto the faith which should afterwards be revealed. Wherefore the law was our schoolmaster to bring us unto Christ, that we might be justified by faith. But after that faith is come, we are no longer under a schoolmaster. For ye are all the children of God by faith in Christ Jesus. For as many of you as have been baptized into Christ have put on Christ. There is neither Jew nor Greek, there is neither bond nor free, there is neither male nor female: for ye are all one in Christ Jesus. And if ye be Christ’s, then are ye Abraham’s seed, and heirs according to the promise" (Galatians 3:23-29).
All men must look to Christ today in order to have salvation.
Scripture comes from God, "Knowing this first, that no prophecy of the scripture is of any private interpretation. For the prophecy came not in old time by the will of man: but holy men of God spake as they were moved by the Holy Ghost" (2 Peter 1:20-21).
And then 2 Timothy 3:16-17 tells us, "All scripture is given by inspiration of God, and is profitable for doctrine, for reproof, for correction, for instruction in righteousness: That the man of God may be perfect, thoroughly furnished unto all good works."
The word comes from God and must be followed without addition or subtraction (Deuteronomy 4:2, Proverbs 30:6, Revelation 22:18-19).
God’s word is given to mankind so that man can know how to follow him. Man comes up with many ideas about religion and how to serve God. In the time of Moses, the Egyptians had numerous gods that they believed in and worshipped. God showed them that he alone is God. Their gods could not compete with him because they were false gods.
Man today can learn from the lessons of the Old Testament. God is the one in charge. He always has been and always will be in charge.
God’s word is plain. It tells of his love for mankind. It tells of how when man sinned, turning away from God, that God planned a way for man to be redeemed, brought back into God’s favor. He sent Christ as the sacrifice for man.
Believe in Christ, turn from sin, confess his name before men and be baptized to have sins removed (Acts 2:38; 22:16). Man can trust in God for salvation, but it must be by obedience to God.