“For I do not desire, brethren, that you should be ignorant of this mystery, lest you should be wise in your own opinion, that blindness in part has happened to Israel until the fullness of the Gentiles has come in. And so all Israel will be saved,as it is written: The Deliverer will come out of Zion; And He will turn away ungodliness from Jacob.” Rom 11:25-26 NKJV

Verses 25 and 26 are Paul’s conclusion built on his reasoning explained throughout Chapter 11. 

The mystery is this: The blindness and “breaking off” of Israel will not continue forever. It will only last until the rest of the “elect” (Zion) are gathered from the Gentile Nations and have been properly engrafted on the “root”.  The root is the Abrahamic promise; “In your seed all the nations of the earth shall be blessed.” (Gen 22:18 NKJV and Gen 26:4, 28:14) “And if you are Christ’s, then you are Abraham’s seed, and heirs according to the promise”. (Gal 3:29 NKJV, Acts 3:25-26)

The “natural” branches (Israel) were broken off because of unbelief and the unbelief was because of an improper condition of heart. This left the opportunity for Gentile believers who “are Christ’s” and a “wild olive tree” to be grafted into the root of the Abraham Covenant. Romans 11:17, "He (Jesus) came unto his own, and his own (Israel as a nation) received him not, but as many as received him (individual Jews and Gentiles) to them gave he liberty to become sons of God." John 1:11-12, Rom 9:23-26 

Acts 10-11:18 records the story of Cornelius and his family. This was the first time the invitation was given to Gentiles to become part of the elect class. “When they heard these things. . . they glorified God, saying, “Then God has also granted to the Gentiles repentance to life.” Acts 11:18 NKJV

Just as only 12 Apostles were called; God is calling a fixed number to be the elect disciples of Jesus. “Elect according to the foreknowledge of God” 1 Pet 1:2  “You are a chosen generation, a royal priesthood, a holy nation, His own special people, that you may proclaim the praises of Him who called you . . .” 1 Pet 2:9 NKJV 

Based on prophetic fulfillments of time and world events, the predetermined number is almost all gathered: the “fullness” of the Gentiles is almost finished.

So the time to favor natural Israel is beginning and Israel’s future will be greatly blessed. “Behold, O My people, I will open your graves and cause you to come up from your graves, and bring you into the land of Israel  . . . Then you shall know that I am the LORD. “ “This is the (new) covenant that I will make with them after those days.” “I will put My law in their minds, and write it on their hearts.” Eze 37:12-14 NKJV, (Heb 10:16, 17, Jer 31:33-34 NKJV) “After those days” refers to the same time as when the fullness of the Gentiles is reached.

When “ungodliness is turned from Jacob (Israel)” Israel’s favor and acceptance of the Messiah will prepare the rest of mankind for a full appreciation of righteousness and godliness during the 1000 year Millennial Age and reign of the King of Righteousness.

The “elect” will come out of “Zion” with Jesus at the Second Advent to first deliver Israel and then the whole world, just as Paul says in Romans 11:26. The deliverance will be from the bondage of sin and Satan into God’s Kingdom.