Book III, 1: On old Wine and new

Old crazy Casks are not designd to hold
New-Wines; nor yet new Vessells, for the Old:
Old must, with Old; and new, with new, be filld:
Else will the vessels breake, and Wine be spilld:
These empty Vessels are thy heart and mine;
The Law and Gospell represents the Wine:
The new's the Spirit, and the old's the Letter;
With reverence to the Text, The new's the better.