The Book of Joshua is an epilogue to the Pentateuch where he finally led Israel into the Promised Land after being in the wilderness for 40 years.
Under the command of Joshua, Israel experienced a brief period of spiritual faithfulness and military success, where there were far fewer instances of covenant breaking in comparison to Moses’ time. This book showed a leadership contrast between Moses and Joshua, hence, the necessity of having Joshua accomplish what Moses could not.
Not only did Joshua share the same name with Jesus in Hebrew, the name meaning salvation, he was also a type of Jesus for the things he did for God’s people. For example, Joshua brought the people across the Jordan to the Promised Land. This event was a prefigure of Baptism by which the People of God received the gift of the Promised Land, an image of eternal life (CCC 1222). Jesus fulfilled the promise of this blessed inheritance in the New Covenant where He brings us to the Promised Land, which is Heaven, through Him — the new and eternal covenant. “He who eats my flesh and drinks my blood has eternal life, and I will raise him up at the last day” (John 6:54).
Joshua’s command in the circumcision of all the sons of Israel shortly after entering the Promised Land was also of great significance to the success of having the people of Israel to behave. For throughout the 40 years in the wilderness under Moses’ leadership, nobody born during that time was circumcised and he failed to have the people keep the covenant.
“Real circumcision is a matter of the heart, spiritual and not literal” (Rom 2:29). Jesus Christ circumcised our hearts at Baptism where there is the outpouring of the Holy Spirit that fills our hearts with God’s love (Rom 5:5), hence, making it truly possible for us to obey the law of God because this love is the fulfillment of all the law (Rom 13:10). Therefore, Joshua was an important type of Christ, for shadowing of our Lord Jesus Christ in the book of Joshua.