It would be dangerous to receive Pompey, since that would make Caesar their enemy.

It would be dangerous to refuse to receive him, as that would make Pompey their enemy, and, though powerless now, he might one day be in a condition to seek vengeance.

It was wisest, therefore, to destroy him.

They would invite him to the shore, and kill him when he landed.

This would please Caesar; and Pompey himself, being dead, could never revenge it.