Growing in sanctification is growing in personal holiness. As such it is a practical, progressive, holiness. It is a growth in holiness that, as Peter puts it in II Peter 1:8, leaves us neither useless nor unfruitful in our knowledge of Him. So then, growing in holiness is also growing in our practical knowledge of Him. Conversely, as our practical knowledge of Him grows, so does our holiness; and as our holiness grows, so does our sensitivity to sin. As such, we will repent more readily and more deeply and more completely.
Additionally, as we grow in sanctification we also grow in our faith; and the heights of holiness we attain are matched by the depth of our faith. Growth in faith gives us a greater ability to trust His Word, to trust in Him, to entrust ourselves over to Him regardless of the situation. This depth of faith is really the bedrock of our sanctification and is the rich soil out of which our holiness grows.
Also, growing in sanctification is also growing in love. It is the enlarging of the heart to love Him more, to love your neighbor more, and to fervently love your fellow Christians. It becomes the great motivation in your living out your Christian life, the great motivation in growing in your faith, the great motivation in your desire for holiness...the great motivation behind the sacrifice and service of your faith. It is this love that gives you the desire, indeed the increasing desire, to please the Lord in every respect. Since all the Law and the prophets are fulfilled in the commands to love God with all our heart, mind, and strength and to love our neighbor as our self; then as we grow in our love for God and neighbor we will also be growing in holiness.
Growing in sanctification, therefore, is not an isolated event, but affects the whole of our spiritual life. There is not an area or aspect of our spiritual life that is not touched. We are set further and further apart from the person we used to be. We become less like that old man, and become progressively more like the new man that is being conformed into the image of Christ; and in the daily renewing of our inner man we grow in all aspects into Him
Growing in sanctification, then, is the progressive reality of our salvation. Friends, I hope this reality is yours.