"Therefore, if any man be in Christ, he is a new creature. Old things are passed away. Behold, all things are become new." 2 Cor. 5:17.
"For even hereunto were ye called; because Christ also suffered for us, leaving us an EXAMPLE, that ye should follow his steps." 1 Pet. 2:21.
The old life perishes, in order that there may be a new creation in Christ. The deformity of the ancient nature passes away, and the image of Christ in the soul takes its place. And we can try and be assured of the truth of the resurrection from the death of sin, only by its likeness to the life of the Savior. It is a matter of great gratitude, therefore, that the Gospel not only delineates holiness, which is but another name for the true inward life, by means of abstract statements; but represents it visibly and sensibly in the beautiful mirror of the Savior's personal history. This is a mirror, which it is necessary for every Christian, and especially for those who are earnestly seeking the entire sanctification of the heart, to contemplate prayerfully and unceasingly. The more we study the life of Christ, if we do it with a consecrated and prayerful spirit, the more it is reasonable to suppose we shall be like him. And in proportion as we bear his likeness, will those various imperfections and inconsistencies, which often mar the lives of his followers, disappear.
— edited from The Interior or Hidden Life (2nd edition 1844) Part 2, Chapter 13 by Thomas Cogswell Upham. You can find more of his work at the blog, The Hidden Life, managed by Craig L Adams at: http://thomascupham.blogspot.com