What would be a Latin phrase similar to the sentiment supposedly expressed by Leonidas the first in 'MOLON LABE' "come and take them" in response to Xerxes demanding the Spartans to lay down their arms? I am mostly concerned with how the sentence would look and what words be used, e.g. venire would simply display the idea of coming but would progredi be more fitting as the original phrase is telling another army to come and take their arms? Another point of word choice would be in the word for 'take', I was thinking sumere or capere but prehendere works well too.
Well, μολὼν λαβέ is a participle with an imperative, so literally it's translated as: "Having come, take"
μολὼν is the masculine singular nominative aorist active participle, which Latin lacks. λαβέ is a simple imperative.
So, if you want to stick closer to the grammar of the Greek, perhaps:
If you want something closer to the English phrase to which it's commonly translated as:
venī et accipe or venī accipeque
Also, looking at the original Greek, βλώσκω is regular ol' word for coming and going, no particular force implied, despite the context. λαμβάνω is also a very general word for take. So if you're looking for it to say "Invade and take them by force" or something to that effect, I'm sad to say the Greek is rather dull. The Spartans were renowned for there laconic wit. So those simple two words were all they needed.