“And the LORD was with Judah; and he drave out the inhabitants of the mountain; but could not drive out the inhabitants of the valley, because they had chariots of iron.” (Judges 1:19)
In Deuteronomy 11:25, God had promised, “There shall no man be able to stand before you: for the LORD your God shall lay the fear of you and the dread of you upon all the land that ye shall tread upon, as he hath said unto you." The Mountainous regions were too rough for the iron Chariots and Judah was able to easily defeat them. They were unable to take the valleys at that time however. It must have seemed that God had broken his promise.
“And they gave Hebron unto Caleb, as Moses said: and he expelled thence the three sons of Anak.” (Judges 1:20)
The only area that was completely free of the previous inhabitants was around Hebron. Caleb had trusted God to give him the victory over the giants the rest had feared, and he was able to drive them out completely. None of the tribes were as successful as he was.
“And the children of Benjamin did not drive out the Jebusites that inhabited Jerusalem; but the Jebusites dwell with the children of Benjamin in Jerusalem unto this day.” (Judges 1:21)
Jerusalem marked the boundary between Judah and Benjamin, although it lay in Benjamite territory. Almost six hundred years later, when David wanted to make Jerusalem his capital, the Jebusites had regained control and he had to fight them to take possession.
“And the house of Joseph, they also went up against Bethel: and the LORD was with them. And the house of Joseph sent to descry Bethel. (Now the name of the city before was Luz.) And the spies saw a man come forth out of the city, and they said unto him, Show us, we pray thee, the entrance into the city, and we will show thee mercy. And when he showed them the entrance into the city, they smote the city with the edge of the sword; but they let go the man and all his family. And the man went into the land of the Hittites, and built a city, and called the name thereof Luz: which is the name thereof unto this day.” (Judges 1:22-25)
The reputation for keeping their promises that Israel had established in their treetment of Rahab and the city of Gibeon enabled combined forces of Ephraim and Manasseh to easily breach the city of Luz’s defenses. Luz was known to the Jews as Bethel, the house of God. It was where Abraham had built his altar and where Jacob saw the vision of the ladder into heaven.
“Neither did Manasseh drive out the inhabitants of Bethshean and her towns, nor Taanach and her towns, nor the inhabitants of Dor and her towns, nor the inhabitants of Ibleam and her towns, nor the inhabitants of Megiddo and her towns: but the Canaanites would dwell in that land.
And it came to pass, when Israel was strong, that they put the Canaanites to tribute, and did not utterly drive them out.” (Judges 1:27-28)
In Exodus 23:28-30, God had promised to drive out the inhabitants of the land as Israel was able to occupy it. “And I will send hornets before thee, which shall drive out the Hivite, the Canaanite, and the Hittite, from before thee. I will not drive them out from before thee in one year; lest the land become desolate, and the beast of the field multiply against thee. By little and little I will drive them out from before thee, until thou be increased, and inherit the land.”
He had and was fulfilling his promise, driving out the groups in the mountains first. Judah wanted to take over the valleys right away, but the valleys enabled the use of superior weapons that they were not able to defeat at the moment. Apparently, God did not feel they were ready for that much land yet.
The problem was that when they became strong enough, and needed the land, the Israelites were more concerned with collecting the tribute from them than in obeying God. In Numbers 33:51-53, God had commanded, “Speak unto the children of Israel, and say unto them, When ye are passed over Jordan into the land of Canaan; Then ye shall drive out all the inhabitants of the land from before you, and destroy all their pictures, and destroy all their molten images, and quite pluck down all their high places: And ye shall dispossess the inhabitants of the land, and dwell therein: for I have given you the land to possess it.” The problem was not that God failed to do his part, but that Israel failed to do theirs. The failure was not limited to a few tribes.
"Neither did Ephraim drive out the Canaanites that dwelt in Gezer; but the Canaanites dwelt in Gezer among them.
Neither did Zebulun drive out the inhabitants of Kitron, nor the inhabitants of Nahalol; but the Canaanites dwelt among them, and became tributaries.
Neither did Asher drive out the inhabitants of Accho, nor the inhabitants of Zidon, nor of Ahlab, nor of Achzib, nor of Helbah, nor of Aphik, nor of Rehob: But the Asherites dwelt among the Canaanites, the inhabitants of the land: for they did not drive them out.
Neither did Naphtali drive out the inhabitants of Bethshemesh, nor the inhabitants of Bethanath; but he dwelt among the Canaanites, the inhabitants of the land: nevertheless the inhabitants of Bethshemesh and of Bethanath became tributaries unto them.
And the Amorites forced the children of Dan into the mountain: for they would not suffer them to come down to the valley: But the Amorites would dwell in mount Heres in Aijalon, and in Shaalbim: yet the hand of the house of Joseph prevailed, so that they became tributaries. And the coast of the Amorites was from the going up to Akrabbim, from the rock, and upward.” (Judges 1:29-36)
Every tribe failed to completely obey God in driving out their enemies, often over extending themselves by trying to drive them all out at once, rather than concentrating on completely eliminating them in the areas they had taken.
“And an angel of the LORD came up from Gilgal to Bochim, and said, I made you to go up out of Egypt, and have brought you unto the land which I sware unto your fathers; and I said, I will never break my covenant with you. And ye shall make no league with the inhabitants of this land; ye shall throw down their altars: but ye have not obeyed my voice: why have ye done this?
Wherefore I also said, I will not drive them out from before you; but they shall be as thorns in your sides, and their gods shall be a snare unto you.” (Judges 2:1-3)
God sent his angel to remind Israel what he had warned them about in Numbers 33:55. “But if ye will not drive out the inhabitants of the land from before you; then it shall come to pass, that those which ye let remain of them shall be pricks in your eyes, and thorns in your sides, and shall vex you in the land wherein ye dwell.” Through out their history, these pockets of other peoples would maintain their false religions and reinfect Israel.
“And it came to pass, when the angel of the LORD spake these words unto all the children of Israel, that the people lifted up their voice, and wept. And they called the name of that place Bochim: and they sacrificed there unto the LORD.” (Judges 2:4-5)