This is an idiom that means "God will bless them with eternal life" or "God will cause them to live forever." (See: [[rc://en/ta/man/translate/figs-idiom]])
# But many who are first will be last, and the last will be first
Here "first" and "last" refer to people's status or importance. Jesus is contrasting people's status now with their status in the kingdom of heaven. AT: "But many who seem to be important now will be the least important, and many who seem to be unimportant now will be very important"