The parallel passage, Luke 6:29, gives the taking of the garments in the converse order. And if any man will sue thee; Revised Version, and if any man would go to law with thee. Notice that "will," "would" ( τῷ θέλοντι), implies that the trial has not yet even begun.
Do this even before it. And take away thy coat, let him have thy cloke also. Coat ( χιτών), equivalent to tunic, "shirt-like under-garment" (Meyer). Cloke ( ἱμάτιον), equivalent to over-cloak, "mantle-like over-garment, toga, which also served for a covering by night, and might not therefore be retained as a pledge over night (Exodus 22:26)' (Meyer).
This is put second, as being the more valuable. In Luke, where there is no mention of the law-court, the thought seems to be merely of the violent removal of the garments, taking them as they came. Let him have ( ἄφες αὐτῷ).
More positive than Luke's "withhold not" ( μὴ κωλύσῃς).