two gatherings of Israel

Prior to the first coming of Messiah, prophecies concerning Messiah were confusing.  There was much debate over whether there would be two Messiahs, one a suffering servant (Son of Joseph) and another a reigning king (Son of David) or if Israel was to do the suffering and the Messiah to do the reigning, etc...   It is now clear that there is one Messiah, and He came once to suffer and die for our sins, then rise in victory and will return again to rule and reign.

Similarly, there has been much confusion about the gathering of Israel together.  

Many get confused when looking at scriptures that talk about a day when Messiah will gather the faithful of Israel together to form a nation, yet there are also scriptures that talk about children of Israel being gathered together not because of their faithfulness, but for the sake of God's Name (completion of His promises, whether Israel is faithful or not) and this gathering of Israel is in preparation for the Tribulation where He will 'sanctify' His people and prepare them for His return where He will gather together the believing remnant. (Isaiah 66:8; Ezekiel 36:17-24)

The closer we get to the time described by prophecy, the clearer and more understandable the prophecy becomes.

It is becoming clear that the nation of Israel formed in 1948 was the gathering of Israel in unbelief for the purpose of the rise of Antichrist, rebuilding the temple, and the Great Tribulation.

After the tribulation, Messiah will return and gather the faithful remnant of Israel, who have repented and accepted Messiah and were preserved through the tribulation to form the nation of Israel that will exist through the millennial reign.

Both gatherings are fulfillment of prophecy, and both gatherings are accomplished according to God's Will and by His hand.

Whether gathered in belief or unbelief, keep in mind that nations are judged according to how they have treated His chosen and the nation of Israel.