The guests at the Marriage feasts will be the Old Covenant (Old Testament and Tribulation) believers who have died. (see also Mark 6:22, 26; Luke 14:16)
Matt 9:15 Jesus answered, “How can the guests of the bridegroom mourn while he is with them? The time will come when the bridegroom will be taken from them; then they will fast.
Matt 22:10 So the servants went out into the streets and gathered all the people they could find, both good and bad, and the wedding hall was filled with guests.