“Everything I meet with, and every day I study my Bible makes me pray more that God would begin and carry on a deep, pure, widespread, and permanent work in Scotland. If it be not deep and pure, it will only end in confusion and grieving the Holy Spirit of God. I am also deepened in my conviction that if we are to be instruments in such a work, we must be purified from all filthiness of the flesh and spirit.
“Oh, cry for personal holiness, constant nearness to God by the blood of the Lamb. Be filled with His Spirit, or all success in the ministry will only be to your everlasting confusion. You know how I have always insisted on this with you. It is because I feel the need thereof myself. Take heed, dear friend. Do not think any sin trivial. Remember, it will have everlasting consequences. Be as holy as God is holy, pure as Christ is pure, perfect as our Father in heaven is perfect. Oh, how much more useful might we be if we were only free from pride, self-conceit, personal vanity, or some secret sin that our heart knows. Oh, hateful sins that destroy our peace and ruin souls.”
(from a letter he wrote to a Pastor friend in 1840)