"[to Nagini, speaking in Parseltongue] The boy has discovered our secret, Nagini. It makes us vulnerable. We must deploy all our forces now to find him. And you, my friend, must stay close."
January 1, 1970
https://en.wikiquote.org/wiki/Harry_Potter_and_the_Deathly_Hallows_%E2%80%93_Part_2