What are the Main differences between old testement and new testement?

Answer 1

Adam's sin caused death to enter the world. Paul in the NT refers to this in a way that can be summed up saying "A life of sin equals death." But the OT shows that God always had a plan to eradicate sin, even the sacrifices and feasts were a "type" or were pointing to one who could overcome sin and death. At Sinai, God made a covenant with His people and when he did, He commanded that His people keep His word (that which was written on stone) on their hearts. The people of God were to keep it there on their own. We know, however, man was not able to keep God's word on their heart and he fell away from God.

In the NT, one who is described as perfect, who knew no sin, died or was put to death. One then can reverse the line in the 2nd sentence above by saying "the death of perfection equals life." Now, God takes what he commanded man to keep on his heart (that which was on stone) and God writes it Himself where He said to keep it in the first place, on the heart.

So the main difference between the two sides of The Bible is one describes doing things according to man's way and failing, not being able to walk in God's will on his own. While the NT shows God interviening in many ways, not the least of which is Him taking His very own Word and writing it on your heart.