sanctification

2 Thessalonians 1:3 "We ought always to give thanks to God for you, brothers, as is right, because your faith is growing abundantly, and the love of every one of you for one another is increasing."

On sanctification. I found the following in the Book of Concord. I put the BoC contents in quotes.

In the larger catechism, when speaking on the Apostles Creed, the third article of the creed "I believe in the Holy Spirit; the holy Christian Church, the communion of saints; the forgiveness of sins; the resurrection of the body; and the life everlasting. Amen."

It's the Holy Spirit that sanctifies us "I believe in God the Father, who has created me; I believe in God the Son, who has redeemed me; I believe in the Holy Spirit, who sanctifies me."

How else can we expect a "change" to happen apart of the Holy Spirit?

"But the Spirit of God alone is called Holy Spirit, that is, He who has sanctified and still sanctifies us. For as the Father is called Creator, the Son Redeemer, so the Holy Spirit, from His work, must be called Sanctifier, or One that makes holy"

"so also the Holy Spirit effects our sanctification by the following parts, namely, by the communion of saints or the Christian Church, the forgiveness of sins, the resurrection of the body, and the life everlasting; that is, He first leads us into His holy congregation, and places us in the bosom of the Church, whereby He preaches to us and brings us to Christ."

"Therefore sanctifying is nothing else than bringing us to Christ to receive this good, to which we could not attain of ourselves."

"Thus, until the last day, the Holy Spirit abides with the holy congregation or Christendom, by means of which He fetches us to Christ and which He employs to teach and preach to us the Word, whereby He works and promotes sanctification, causing it [this community] daily to grow and become strong in the faith and its fruits which He produces."

"Meanwhile, however, while sanctification has begun and is growing daily, we expect that our flesh will be destroyed and buried with all its uncleanness, and will come forth gloriously, and arise to entire and perfect holiness in a new eternal life."