Man is in a covenant relationship with God, and sin is the breaking of this covenant. This is especially the witness of the prophets who insist that sin is a rebellion against God. Sin against God, or against one's fellow man who is a member of the covenant people, is all ethically responsible act. Social sin and religious sin are both against God. Man's relationship to God as a person is at the basis of the covenant.
Sin is more than breaking a law, it is a defection from the one who gives the law.
External laws were seen as the will of Jehovah. Personal responsibility and the motive of the heart are emphasized. Indeed, one can sin even when he externally keeps the law. The concepts of sinfulness and a sinful nature are also seen in the Old Testament. A keen awareness of the sinful state of the heart is evident.