1) “Stay dressed for action.”
The literal translation of this phrase is, “let your loins be girded”.
2) "Have your lamps lit." Not only are followers of Christ supposed to get something prepared, in this case a lamp, but they are responsible to constantly provide fuel for the lamp so that they remained prepared.
3) Jesus likens himself to a master who is gone at a wedding and his followers (as servants) waiting for his return. This part of the parable foreshadows what Jesus eventually does for his own disciples and what he will do for all of his followers when he comes back again.
4) A master being robbed by a thief to communicate the surprise of his return. (Revelations 3 mentions this word "thief".)