"who are united to the Lord and die." This may refer to people who are killed by their enemies. Alternate translation: "who die because they are united to the Lord"
These deeds are spoken of as if they were alive and able to follow those who did them. Possible meanings are 1) "others will know the good deeds these people have done" or 2) "God will reward them for their deeds" (See: [[rc://en/ta/man/translate/figs-personification]])