Promise and fulfillment in the Bible - Two illustrations
The first one illustrates the promise and fulfillment process.
Let’s imagine that I promise to give you a priceless gift of a diamond. Even though it is a free gift and I’m not bound to offer it to you, I write you a promissory note, which obligates me to fulfill my promise (note the word "promise" in "promissory"). A month later, I give you the diamond. My promise has been fulfilled, and the diamond is far better than the promise. You now enjoy the reality of the diamond without any fear that I will change my mind. It is finished. And you are grateful, not confused or insecure.
This is like the promise of salvation in Isaiah 53 and a New Covenant in Jeremiah 31. God promises (promissory note) to send the Messiah and a New Covenant (both represented as one priceless diamond). Around 700 to 500 years later, God fulfills his promise and gives us Christ as our salvation and our New Covenant. Now we can benefit from the original promise and its fulfillment. Everything has been paid in full. And the reality of God’s gift of salvation and a Covenant is much better than the promise. However good and sacred the promises and prophecies were, they were mere words by comparison to their reality. We are grateful for the "new thing" that God has brought about (Isaiah 42:9, 43:19, and 48:6).
A similar (but not identical) illustration explains the Quran’s abrogation process.
Let’s imagine that I give you a priceless gift of a diamond (a Quranic revelation). But then a week later I see you on the street wearing the diamond. Without advance notice I walk up to you, take the diamond away, and replace it with another diamond—maybe of a higher quality (though Sura 2:106 does not guarantee this). The second diamond may be merely "similar to" or "like" the first. My only explanation is that circumstances have changed, so the first diamond must be taken away. How does this make you feel secure? What if other circumstances arise later? Will I take the second diamond from you? Theoretically, the process could go on indefinitely. You are right to question my character and stability. I seem fickle because I am tied down to immediate circumstances that I am unable to anticipate.
This is like Quranic abrogation. A verse is sent down, but in a short time it is canceled and replaced with a similar or better verse after circumstances change. Anyone has a right to question the character and stability of this deity. He seems tied down to immediate circumstances that he is unable to anticipate.