What is the meaning of law according to Bible?

The revelation of the will of God in the Old Testament and later elaboration on law are referred to as "traditions of the elders" in the New Testament (Matt. 15:2; Mark 7:5; Gal 1:14). Law may be used for a commandment, a Word, a decree, a judgment, a custom, or a prohibition. The first five books of The Bible (the Pentateuch) are known as the books of the law (Hebrew Torah, teaching) because they are based on the Commandments that God revealed to Moses.

Another Answer:

From the beginning, the whole intent and purpose of the Ten Commandments is love because 'God is love' (1 John 4:16). Jesus taught us that God's law has two basic aspects: the first to show us how to love God (1st four Commandments); the second shows us how to love our neighbor or fellow human beings (last 6 Commandments).

Both James (James 1:22-25) and Paul (Romans 7:7) tell us the law of God is like a spiritual mirror into which we may look to find our spiritual dirt - sin - on our minds and heart. The mirror functions to show us this dirt in each of us and is not responsible for it or the harm it may surely cause. It is up to each individual to 'repent' or change one's sinning ways and become cleansed (forgiven), becoming free from fears, from misery, from the penalties of sin - the bondage of Satan's way as the god of this world. God's law is good in that it is just and holy (Romans 7:12).

God is wanting to forgive all who turn away from sin as many Scripture shows:

Ezekiel 18:21-22New International Version (NIV)

21 "But if a wicked person turns away from all the sins they have committed and keeps all my decrees and does what is just and right, that person will surely live; they will not die. 22 None of the offenses they have committed will be remembered against them. Because of the righteous things they have done, they will live.