“You can have.” The Greek word is echō (#2192 ἔχω), which is usually “you have,” but in this case it can be “you can have” (see BDAG, ἔχω, definition 9).
“a guard of soldiers.” The Greek word is koustōdia (#2892 κουστωδία), a guard of Roman soldiers. The Pharisees and chief priests were so filled with trepidation about Jesus that they went to Pilate and requested a guard to keep the tomb secure (Matt. 27:62-66). Pilate’s answer as it appears in many English versions, “You have a watch,” or “You have a guard,” has sometimes been misunderstood to mean that Pilate told the priests that since they already had the Temple police, they should use them. That is not correct. Pilate gave permission to the priests to requisition a detachment of Roman guards, which is why those soldiers would have been in trouble if the governor heard that the guard and fallen asleep and the body of Jesus had been stolen (Matt. 28:12-15). Pilate would not care if the Temple police had fallen asleep and Jesus’ body had been stolen.