The document discusses two types of rest: the rest of Joshua and the Sabbath rest of Hebrews 4. [1] The rest of Joshua lasted only one generation as the Israelites were unable to fully drive out the Canaanite people from the land due to their iron chariots. [2] In contrast, the Sabbath rest of Hebrews 4 is an eternal rest offered by Christ who understands our weaknesses and was tempted without sinning. It provides assurance of access to God's grace and mercy.