The conditions broken were met with temporary expulsions from the Land as a chastisement. His promise to regather them back into the Land was UNCONDITIONAL.
(Is. 11:11-12 NASB) Then it will happen on that day that the Lord will again recover the second time with His hand the remnant of His people, who will remain, from Assyria, Egypt, Pathros, Cush, Elam, Shinar, Hamath, and from the islands of the sea. 12And He will lift up a standard for the nations, and will assemble the banished ones of Israel, and will gather the dispersed of Judah from the four corners of the earth.
And I will bring again the captivity of my people of Israel, and they shall build the waste cities, and inhabit them; and they shall plant vineyards, and drink the wine thereof; they shall also make gardens, and eat the fruit of them. And I will plant them upon their land, and they shall no more be pulled up out of their land which I have given them, saith the LORD thy God. (Amo 9:14-15)
For, behold, in those days, and in that time, when I shall bring again the captivity of Judah and Jerusalem, I will also gather all nations, and will bring them down into the valley of Jehoshaphat, and will plead with them there for my people and for my heritage Israel, whom they have scattered among the nations, and parted my land.
(Joe 3:1-2)
For I will take you from among the heathen, and gather you out of all countries, and will bring you into your own land. (Eze 36:24)
And say unto them, Thus saith the Lord GOD; Behold, I will take the children of Israel from among the heathen, whither they be gone, and will gather them on every side, and bring them into their own land: And I will make them one nation in the land upon the mountains of Israel; and one king shall be king to them all: and they shall be no more two nations, neither shall they be divided into two kingdoms any more at all:
(Eze 37:21-22)