In Gen. 12:1, the LORD promised Abram,
“Go forth from your country,
And from your relatives
And from your father’s house,
To the land which I will show you”
This promise was elaborated in Gen. 15:13-21
13 God said to Abram, “Know for certain that your descendants will be strangers in a land that is not theirs, where they will be enslaved and oppressed four hundred years ...16 Then in the fourth generation they will return here ...” 18 On that day the LORD made a covenant with Abram, saying, “To your descendants I have given this land, From the river of Egypt as far as the great river, the river Euphrates ...” (cf., Exo. 23:31).
Fulfilment of land promise: Then in Josh. 21:43-45 ...
43 So the LORD gave Israel all the land which He had sworn to give to their fathers, and they possessed it and lived in it. 44 And the LORD gave them rest on every side, according to all that He had sworn to their fathers, and no one of all their enemies stood before them; the LORD gave all their enemies into their hand. 45 Not one of the good promises which the LORD had made to the house of Israel failed; all came to pass.
Israel possessed the land in that they occupied it but Judg. 2:20-23 states,
20 So the anger of the LORD burned against Israel, and He said, “Because this nation has transgressed My covenant which I commanded their fathers and has not listened to My voice, 21 I also will no longer drive out before them any of the nations which Joshua left when he died, 22 in order to test Israel by them, whether they will keep the way of the LORD to walk in it as their fathers did, or not.” 23 So the LORD allowed those nations to remain, not driving them out quickly; and He did not give them into the hand of Joshua.
The land promise was considered fulfilled even though Canaanites still lived in the land then. Exo. 23:29-30 promised that the Canaanites would be driven out little by little till the Israelites eventually possessed the land.
And we read in 1 Kgs. 4:21 that 21 ... Solomon ruled over all the kingdoms from the (Euphrates) River to the land of the Philistines and to the border of Egypt; they brought tribute and served Solomon all the days of his life.
The extent of Solomon’s kingdom from the Euphrates River to the border of Egypt seems to correspond to the land promised to Abram as between the river of Egypt and the river Euphrates (Gen. 15:18).
However, one may argue that Solomon did not possess nor occupy all the land as the vassal kingdoms (who paid tribute to Solomon) were still ruled by their own kings.
Warning of exile (from the land) - After the death of Solomon, the kingdom was split into two: Israel in the north and Judah in the south. Israel, the northern kingdom had 19 kings; all were evil and caused the people to turn away from God. Judah, the southern kingdom had 19 kings and 1 queen; many were bad and a few good. God sent prophets to warn the people of the consequence of their sin and to pronounce His judgment upon them. This judgment was destruction by the hands of foreign invaders and exile to Babylon.
Isaiah prophesied of the exile to Babylon after King Hezekiah showed off his treasures to envoys from Babylon ... “Behold, the days are coming when all that is in your house … will be carried to Babylon; nothing will be left,” says the LORD. “And some of your sons … will be taken away, and they will become officials in the palace of the king of Babylon.” (Isa. 39:6-7). This warning of dispersion for disobedience goes all the way back when the Israelites were wandering in the wilderness … "So it shall be when all of these things have come upon you, the blessing and the curse which I have set before you, and you call them to mind in all nations where the LORD your God has banished you (Deut. 30:1).
Promise of return and regathering (back to the land) - But there was also a promise of regathering for repentance “… return to the LORD your God and obey Him with all your heart and soul according to all that I command you today, you and your sons, then the LORD your God will restore you from captivity, and have compassion on you, and will gather you again from all the peoples where the LORD your God has scattered you. The LORD your God will bring you into the land which your fathers possessed, and you shall possess it; and He will prosper you and multiply you more than your fathers”
(Deut. 30:2-3,5).
The return to the land was started around 538 BC during the reign of King Cyrus of Persia when Jews were allowed to return to their land and rebuild the temple (Ezra 1:1-4). From history, we know that Israel was once again dispossessed of its land in AD 70 with the destruction of Jerusalem. With the establishment of Israel as a nation in 1947, Jews have begun to return to their land.
However, the prophets Jeremiah, Isaiah and Ezekiel prophesied a regathering of every Israelite to their land from four corners of the earth (Jer. 16:14-16; Isa. 43:1-7; Ezek. 39:28) and this has YET TO HAPPEN; a large population of Jews are still in the United States.