Augustus Toplady wrote:
Rock of Ages, cleft for me,
Let me hide myself in Thee;
Let the water and the blood,
From Thy riven side which flowed,
Be of sin the double cure,
Cleanse me from its guilt and power.
This “double cure” is both justification and sanctification. Each is a separate work, yet they are inseparable because both flow from union with Christ. From this union flows justification, which takes care of the guilt of our sin, and sanctification which takes care of the power of sin over our lives.
Brian Borgman, who I highly recommend, preaches a wonderful sermon regarding this topic which can be either watched or listened to here.