Joshua 1

With Moses dead, Joshua becomes the military leader of the Israelites. The men of those tribes that have been given land east of the Jordan (Reuben, Gad, and Manasseh of the tribe of Joseph) are to be required to leave their wives and children and lead the communal expedition to seize Canaan. Then "they," presumably the officers of the Israelites swear absolute fealty and impose the death penalty on any who defy Joshua. Their only requirement of him is to be strong and resolute.

God's commands and promises are somewhat different.

He promises:

• to give Joshua every place on which he sets foot
• a territory extending north-south over the general area of Israel, but to the east as far as the Euphrates over much of modern-day Syria, Iraq and Saudi Arabia
• that no one can stand against Joshua
• that God will never leave Joshua
• provisional on obeying the law, that Israel will be prosperous and successful.

These appear to be personal promises, more specific to Joshua than to Israel.

He commands Joshua to:

• be strong and (very) courageous, the same demand as the people make on Joshua
• meditate night and day on the Law and do not deviate from it
• not be discouraged or terrified
  

In understanding the conquest of Canaan, it is worth remembering that in Genesis 9: 25, Noah curses his grandsom Canaan, the son of Ham, for having seen his father's nakedness (possibly a euphemism for some sexual mischief), saying "The lowest of slaves will he be to his brothers."

Jamieson says that Joshua's original name was Osher (Num 13:8) and changes into Jehoshua, meaning "God's salvation", in this book (http://www.blueletterbible.org/tmp_dir/c/1092719465-7276.html)

Matthew Henry notes that Joshua is the prototype of Jesus, and that the Septuagint actually translates "Yehoshuah" as "Jesus" (http://www.blueletterbible.org/tmp_dir/c/1092718889-5323.html)

The conquest of Canaan as recorded in the book of Joshua is through bloody conquest. Yet in Exodus 23, God promises an essentially bloodless conquest, with confusion, terror, and the hornet doing battle for the Israelites. One might ask whether the original Israelite rebellion against the invasion, recorded in Numbers 13-14, was punished by imposing on their descendants who engaged in the invasion the penalty of blood.