Why are Hector and Paris dinning with king Menelaus of sparta?

I wish you has given the section number for this, but I'll give it my best shot. Paris and Hector are dining with Menelaus is celebration of his marriage. It was here that all of Helen's suitors promised to give Melenaus aid should he ever need it.

There's a later dinner where Paris is present by himself; this dinner denotes his decision to take Helen away with him.