"There is a call to gallows, friends,
will any of you go!
Those who do talk of love may Know
to gallows they must speed."
The stanza says that a lover will speed up towards gallows when he is called up as this will prove him a "true lover"
Gallows is an instrument of execution consisting of a wooden frame from which a condemned person is executed by hanging.
So is he saying that death will prove you a true lover?
Death will quench your thirst?