John Ball was an English Puritan who ministered in the early 17th Century. He wrote a stellar book I am now reading called "A Treatise on the Covenant of Grace". It is a riveting work I can't put down (literally, because I have to finish chapter summaries right quick). I'm not a big fan of the old English letter "S" being a "F" (See above), but oh well. Here's a rich statement by Ball (with the right kind of "S")-
"Faith alone is the cause of Justification and Salvation, on our part required. It is a penitent and petitioning faith, whereby we receive the promises of mercy, but we are not justified partly by prayer, partly by repentance, and partly by faith, but by that faith, which stirreth up godly sorrow for sin, and enforceth us to pray for pardon and salvation. Faith is a necessary and lively instrument of Justification...If it be demanded whose instrument is it (faith)? It is the instrument of the soul, wrought therein by the Holy Ghost, and is the free gift of God."