Patrick O’Brian. Ships, storms, battles, expeditions, people marooned on islands, giant tortoises, guns, shipwrecks, mutiny, revolution, ropes and rigging, tropics and icebergs, and the dead sewn up in their hammocks with a couple of roundshot at their feet. And sealed orders.
Sealed Orders are the orders given the commanding officer of a ship or squadron that are sealed up, which he is not allowed to open until he has proceeded a certain length into the high seas; an arrangement in order to ensure secrecy in a time of war. So that you might send a squadron out to suppress the slave trade off the Ivory Coast, and nobody knows until they reach a particular point of latitude and longitude that the squadron is also ordered to intercept a French invasion of Ireland.
In the gospel, there are no sealed orders.

what I say to you in the dark, tell in the light
what you hear whispered, proclaim from the housetops

But we tend to assume there must be. (Gnostics.) We write our own, and open the envelope whenever it suits us. (Christian Family Values.) There aren’t. This is worth noticing. What I say to you in the dark, tell in the light. What you hear whispered, proclaim from the housetops.
These are not sealed orders, then, but they are orders. Marching orders. Jesus is talking to his disciples, sending them out. He does what it’s natural to do in that situation. He tells them who they are and how they will be known. They’re going out, and there will be trouble. People are not going to like this at all. Things will happen that are wholly unpredictable except that they can be relied on to be bad. For more on that, read Jeremiah.
Jesus can’t give them instructions for everything that will happen to them; again, they have no sealed orders; he tells them who they are and how they will be known. He talks about integrity, which is about sticking to who you are and where you belong.

those who acknowledge me, I will acknowledge
those who deny me, I will deny

He talks about identity, which is about knowing where you belong and who you are.
Where do they belong? In a company, a household, a family.
Who are they? Recognised. Recognisable.
They haven’t got sealed orders. They have news for people instead. They haven’t got a checklist or targets or a set of ideas. They are a people with a history and a hope.