Land promises of Gen 15 completely fulfilled according to OT Scriptures:
God promised 6 cities of refuge:
Deu 19:7-0
Therefore, I command you, saying, 'You shall set aside three cities for yourself.' "If the LORD your God enlarges your territory, just as He has sworn to your fathers, and gives you all the land which He promised to give your fathers— if you carefully observe all this commandment which I command you today, to love the LORD your God, and to walk in His ways always—then you shall add three more cities for yourself, besides these three.
Joshua 20:7-9 lists six cities of refuge - Kadesh, Shechem, Hebron, Bezer, Ramoth, and Golan.
7 And they appointed Kedesh in Galilee in mount Naphtali, and Shechem in mount Ephraim, and Kirjath-arba, which is Hebron, in the mountain of Judah. 8 And on the other side Jordan by Jericho eastward, they assigned Bezer in the wilderness upon the plain out of the tribe of Reuben, and Ramoth in Gilead out of the tribe of Gad, and Golan in Bashan out of the tribe of Manasseh. 9 These were the cities appointed for all the children of Israel, and for the stranger that sojourneth among them, that whosoever killeth any person at unawares might flee thither, and not die by the hand of the avenger of blood, until he stood before the congregation.
God stated that all the land promises were fulfilled in Joshua 21:
43-45 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. 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. Not one of the good promises which the Lord had made to the house of Israel failed; all came to pass.
And again in Joshua 23:
14-15 Now behold, today I am going the way of all the earth, and you know in all your hearts and in all your souls that not one word of all the good words which the Lord your God spoke concerning you has failed; all have been fulfilled for you, not one of them has failed. "It shall come about that just as all the good words which the Lord your God spoke to you have come upon you, so the Lord will bring upon you all the threats, until He has destroyed you from off this good land which the Lord your God has given you.
Josh 24:28 Then Joshua dismissed the people, each to his inheritance.
2 Sam 8:3 David defeated Hadadezer...as he went to restore his rule at the River [Euphrates].
1 Kings 4:21 Now 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
2 Chr 9:26 And he was the ruler over all the kings from the Euphrates River even to the land of the Philistines, and as far as the border of Egypt.
Neh 9:8 And Thou didst find Abraham's heart faithful before Thee, and didst make a covenant with him to give him the land of the Canaanite, of the Hittite and the Amorite, of the Perizzite, the Jebusite, and the Girgashite-- to give it to his descendants. And Thou hast fulfilled Thy promise, for Thou art righteous.
Jer 11:5 in order to confirm the oath which I swore to your forefathers, to give them a land flowing with milk and honey, as it is this day. Then I answered and said, "Amen, O LORD."