Dinner. Greek ariston, originally meaning the first meal, or breakfast, but used later to refer to the noon meal.
Supper. Greek deipnon, usually refer to the evening meal.
Call not thy friends. According to the Greek the thought may be summed up, “Do not be in the habit of always inviting only your friends.” Jesus does not exclude the entertainment of friends, but rather warns against the selfish motives that lead many to entertain only those from whom they expect similar courtesies. Jesus encourages hospitality on the basis of genuine interest in the needs of our fellow men — perhaps the need for food, perhaps the need for friendship. He points out that this kind of hospitality, though not returned in the present life, will be rewarded in the life to come.
Again. That is, in return for the previous invitation.