Joshua, a type of the Lord Jesus, was a successor to Moses. But there was no successor to Joshua. It was necessary for Israel to have a designated leader to establish them in their land, then the people were left responsible to subdue their enemies in their own territory and possess all the land. But the faith of the people soon waned badly, so that the book of Judges stands in sad contrast to the book of Joshua. Again and again Israel lapsed into a state of departure from God, and over and over again God raised up a judge or a deliverer to rescue them from their enemies. A similar tragedy has occurred in the professing Church of God. After the apostles laid the foundation by which the Church was established, no leader was designated by God to continue the apostle's work, for the Holy Spirit had been given to all believers (Acts 2:1), and the Word of God also given, by which all believers unitedly were furnished with all that was necessary to maintain a godly witness to the truth. But the history of the Church has been one of failure and disobedience, relieved only on occasion by God's intervention in revival, but in general sinking lower and lower, so that today a spirit prevails everywhere such as is expressed inJudges 21:25, "everyone did what was right in his own eyes."
The first chapter of Judges (up to verse 19) shows that Israel did have ability given of God to act for Him and drive out their enemies, even though Joshua had died. If they had continued to depend on God in genuine faith, their victories would have continued also. But at the end of verse 19 the breakdown began that very soon crippled the strength of the nation, so that what began well ended in dismal failure.