Scriptures in the Old Testament taught - the Word was to be "hid" in the heart so that Jewish people would not sin against God.
Psalm 119:11...Thy word have I hid in mine heart, that I might not sin against thee.
The Word of God was the Law and Commandments. The Torah was the first five books in the Bible. The 613 Commandments were the standard of God given to Jewish people to keep Israel in "obedience" to the God.
In that day and hour before the death of Christ; before Grace flowed from the Cross at Calvary; and before the Holy Spirit developed the Church, the body of Christ...The commandments were "learned and lived" by the Jewish people as a act of faith in God.
In order for Israel to be holy they were to learn, study, and meditate the Law and Commandments contained in the Torah. By doing such Israelite's were able to grasp and absorb the standards of God's Law - which forbid sin and sinful conduct. God's Law pointed out sin and told the recipient "to do" or "not to do" certain things that were outside of God's standard.
James 2:10...For whosoever shall keep the whole law, and yet offend in one point, he is guilty of all.
If the Word was hid or absorbed into the heart it was able to keep man from sinning against the Law of God. Sin was and is a violation to the Law of God.
The Law and 613 commandments given to Israel on Mt. Sinai were the greatest set of morals ever written...before Christ died. After the death of a Savior on the Cross....Grace came and allowed God's Holy Spirit to provide a moral standard of holiness much greater than the holiness of Law. It was the holiness of the Spirit of God that writes the Law of God - upon the the tables of a believing heart.
Hebrews 10: 15,16...Whereof the Holy Ghost also is a witness to us: for after that he had said before, This is the covenant that I will make with them after those days, saith the Lord, I will put my laws into their hearts, and in their minds will I write them;
In the Old Testament Israel worked and hid the Word in their heart to keep the standard. In the New Testament we hold on to Christ and by doing such we live the standard of God...according to the Spirit of holiness. A blessing of the New Testament and the power of God's Grace.
As the Apostle Paul stated,
Romans 6:14...For sin shall not have dominion over you: for ye are not under the law, but under Grace.