Covenant not contract....

I was interested in finding out the difference between a covenant and a contract. I stumbled across the Greek word Diatheke, which means: covenant or (last will and) testament.

I'm not normally into the Greek translation, but I figured it couldn't hurt.

I took this next passage from a Lutheran Church website:  

An attention getter—John 3:16. Ask a crowd of believers for the most famous passage in the Bible. "JOHN 3:16!" a large percentage of them will reply. Isn't it interesting that this passage just happens to be in "testamental" form?

When a person goes to an attorney to draw up his "last will and testament," five things are usually involved: (1) a testator, the one who makes the will; (2) heir(s); (3) a method of effectuation, the way by which a testament goes into effect (by death); (4) a testator's promissory signature, which validates—through his word of promise—that which will be given to the heir(s); and (5) the actual inheritance to be left behind.¹⁴

John 3:16: "For God (the Testator) loved the world (the heirs) so much that He gave (into death) His one-and-only Son, so that everyone who believes in Him would not perish (the Testator's signature by word of promise) but have everlasting life (the inheritance)." Amazing!http://www.redeemerlutheranchurch.org/diatheke.htm

Though one definition of covenant is contract,  it seems deeper. A contract ends once something is fulfilled, a covenant is like devotion. (forgive me if I'm just getting on a soapbox.)

Hebrews 8:

8:... Behold, the days come, saith the Lord, when I will make a new covenant with the house of Israel and with the house of Judah: 9: Not according to the covenant that I made with their fathers in the day when I took them by the hand to lead them out of the land of Egypt; because they continued not in my covenant, and I regarded them not, saith the Lord. 10: For this is the covenant that I will make with the house of Israel after those days, saith the Lord; I will put my laws into their mind, and write them in their hearts: and I will be to them a God, and they shall be to me a people. God's covenant is forever.  We are his Beloved so we get to be his inheritance