Duplex Gratia
The twin benefits of the duplex gratia that stem from (Spirit-worked) union, justification and sanctification/ ongoing Spirit worked renewal, are as distinct from each other and unconfused as they are undeniably inseparable. In fact, it seems fair to Calvin to say that this twofold distinction (between justification and sanctification) is, in effect, the distinction between grace as forensic and nonforensic, a distinction that as such is irreducible.
Richard Gaffin, "Justification and Union with Christ," in Theological Guide to Calvin's Institutes, eds. David Hall and Peter Lillback (Philippsburg, NJ: P&R Publishing, 2008), 262