Συνχάρητέ [2 verses](verb 2nd pl fut ind act or verb 2nd pl aor imperat pass ) "Rejoice" is sygchairō which means to "rejoice with", "wish one joy", and "congratulate." -- "Rejoice" is another Greek verb used for the first time here. It consists of the more common word for "rejoice" with the prefix meaning "together". It means  "rejoice with", "wish one joy", and "congratulate." The form is not an active command as translated. It is most likely the future tense statement,  "together you will celebrate ". If it was a command, it would have to be passive which would be "Be celebrating together"