The greatest instrument of sanctification?

A friend on Facebook shared a quote from an evangelical preacher who opined that marriage is the "greatest instrument of sanctification."

"greatest"

Really? I question this for several reasons. 

- Does that mean those of us who are single, divorced, or widowed will be incompletely sanctified? 

- Is the marriage relationship the instrument or the environment where sanctification takes place. If it is the former, then it goes against the 1689 London Baptist Confession 13.1:

"They who are united to Christ, effectually called, and regenerated, having a new heart and a new spirit created in them through the virtue of Christ's death and resurrection, are also farther sanctified, really and personally, through the same virtue, by His Word and Spirit dwelling in them; the dominion of the whole body of sin is destroyed, and the several lusts thereof are more and more weakened and mortified, and they more and more quickened and strengthened in all saving graces, to the practice of all true holiness, without which no man shall see the Lord. ( Acts 20:32; Romans 6:5, 6; John 17:17; Ephesians 3:16-19; 1 Thessalonians 5:21-23; Romans 6:14; Galatians 5:24; Colossians 1:11; 2 Corinthians 7:1; Hebrews 12:14 )"

- If marriage is the instrumental means of our sanctification, the logic in the top quote can be used to keep a woman in an abusive marriage. It will keep her from naming abuse for what it is. She can never be free because it is her primary means of sanctification. But she is sanctified by Christ through the Spirit and the Word, not her abuser.

- We need to be careful with our words. The quote in question is similar to another pet peeve of mine, "Marriage is the gospel." I have a hard time confessing that marriage became incarnate. Marriage lived a perfect and righteous life in my place. Marriage died to pay the penalty for sin I should have paid. Marriage was buried, rose again 3 days later, and is ascended to heaven on the right hand of the Father. We are awaiting the return of Marriage and the resurrection. Now if you want to say marriage can be an example of the sacrificial love of Christ for his church when a husband does likewise for his wife, I will affirm that. 

- I have no problem affirming that marriage is a good and godly thing. I have no problem affirming that marriage as well as other relationships are environments where the Holy Spirit can apply the Word to our hearts to further our sanctification. But I can't agree with making a temporal relationship synonymous with the work of the third person of the Godhead. If we make marriage salvific, it can lead to the following, which I regret to say is what you will find in some Christian women's books:

"In this you greatly rejoice, though now for a little while, if need be, you have been grieved by marriage, that the genuineness of your faith, being much more precious than gold that perishes, though it is tested by fire in your marriage, may be found to praise, honor, and glory at the revelation of Jesus Christ, whom having not seen you love. Though now you do not see Him, yet believing, you rejoice with joy inexpressible and full of glory, receiving the goal of your marriage—the salvation of your souls through marriage." ht: Don Owsley