"Now may the God of peace himself sanctify you completely, and may your whole spirit and soul and body be kept blameless at the coming of our Lord Jesus Christ. He who calls you is faithful; he will surely do it" (1 Thess. 5:23-24).
To be sanctified and kept blameless, this is the goal, but whose job is it to accomplish this? Some passages, and some teachings, seem to indicate that it's our job. Other passages, such as this one, seem to indicate that it's up to God. So which is it? The debate over this question is a very old one but the real problem comes whenever we go too far in either direction. To say that it's all God's work and we have nothing to do with it denies the Bible's teaching of obedience and personal responsibility. To say that it's completely our own work to sanctify ourselves and be pure before God denies the need for the grace of God and the blood of Christ. The truth is, God has a work he does in santifying us, a work we could never accomplish for ourselves. It is the blood of his son and his love and provision that makes our sanctification possible. But, at the same time, not in a contradiction, but in harmony with God's grace, we too must do something. We must receive his word, believe it, and be obedient and faithful to it. To do so is not to earn our salvation, it is to respond to his grace and meet the conditions he requires of us.
Even though we may understand all of this theologically, let's make sure we also live all of this practically. It's possible to be able to speak the doctrine correctly, but still live the doctrine falsely. For example, if I never seek God's help, grace and provision in sancitfying me and helping me to be blameless, I'm living a false doctrine. On other other hand if I accept sin in my life and live in disobedience but shrug my shoulders and say that God will take care of it, I'm living a false doctrine.
May we all pursue truth not only in study and teaching, but in practical application. May we seek God's grace to sanctify us and also pursue obedience that we may be found pleasing to him.