Paul and John Owen say: Christian, Make war on sin!

PAUL
First Century Christian Apostle
"Put to death therefore what is earthly in you."

Read more of Paul's thoughts on Mortification of Sin here and here and here.

JOHN OWEN
Seventeenth Century Christian Theologian
"Be killing sin, or it will be killing you."

Read a summary of John Owen's Mortification of Sin here.
Read the full text of John Owen's Mortification of Sin here.