In what, then, are justification and sanctification alike? (a) Both proceed originally from the free grace of God. It is of His gift alone that believers are justified or sanctified at all. (b) Both are part of that great work of salvation which Christ, in the eternal covenant, has undertaken on behalf of His people. Christ is the fountain of life, from which pardon and holiness both flow. The root of each is Christ. (c) Both are to be found in the same persons. Those who are justified are always sanctified, and those who are sanctified are always justified. God has joined them together, and they cannot be put asunder. (d) Both begin at the same time. The moment a person begins to be a justified person, he also begins to be a sanctified person. He may not feel it, but it is a fact. (e) Both are alike necessary to salvation. No one ever reached heaven without a renewed heart as well as forgiveness, without the Spirit’s grace as well as the blood of Christ, without a meetness for eternal glory as well as a title. The one is just as necessary as the other.
~ J.C. Ryle (1816-1900)
A Prayer Life 