According to Vine's Complete Expository Dictionary of Old and New Testament Words, the word, "commandment" is used 118 times in the Old Testament. These do not include synonymous words such as "statutes," "ordinances," "laws," etc. Vine's doesn't even mention that it is found in the New Testament, where it appears thirty times! I do not recommend Vine's for many reasons, but it is neither expository nor complete. Vine's does not even define the word! Nevertheless, Vine's is all I have so I am stuck with it.
Webster defines "commandment" as "an authoritative command or order; mandate; precept; specifically any of the Ten Commandments." While the first part of the definition is accurate, there are commandments in the Word long before the Ten Commandments were given to Moses. Abraham was praised by God in Genesis 26:5, where He says, "Because that Abraham obeyed My voice, and kept My charge, My commandments, My statutes, and my laws." According to what I have been taught over forty years, the Old Testament contains 613 laws, or commands; I have not counted them, but that sounds reasonable. It is my belief that the Ten Commandments cover all of God's will for His people, and that the other 603 fit within "The Ten." It is as though God gave Moses "an outline" of all of His "Rules" and then, over time, gave Israel the details.
Jesus had a few things to say which may clarify our understanding of the commandments of God: 1). There are varying levels of significance among the "613" (Matt. 5:19). 2). Both Jesus and the Father had commandments, and I am absolutely certain that they did not contradict each other (Jn. 3:34; 14:10; 15:10; 17:8). 3). There are false commandments made up to subjugate the people of God (Matt. 15:1-9). 4). The commandments from the Law and the Prophets (a way of saying all of the Old Testament) can be summed up in just two commandments: Love God and Love your neighbor (Matt. 22:37-40).
Christians are not bound by the 613 laws of Israel (Gal. 3:23-25). Christians have really only one commandment: "Love they neighbor as thyself" (Matt. 5:43-48; 7:12; 22:40; Rom. 13:8-10; 1 Thes. 3:11-13; 1 Tim. 1:5; 1 Jn. 3:23). This is nothing new, for the Father had said the same thing to Israel in Leviticus 19:18. Christians are to judge their own thoughts, words, and actions by whether or not they are expressions of love; if not, they are sin! We have only one, but even it makes us aware that we needed a Savior. Thanks be to God for sending His Son that you and I might have eternal life. Loving God is easy.