Ralph Erskine (The Nature and Excellency of Purity opened), Sermons 1:312-313:
Gospel purity inclines a man to make advances in religion. He forgets the things that are behind and presseth forward. He can never be pure enough: he goes from strength to strength. “The path of the just is as the shining light, that shineth more and more unto the perfect day.” It is true, there are ebbings and flowings of grace. The person may be going sometimes backward, at other times forward, but his ordinary course is like the sun: it may be under a cloud and out of view, as if there was no sun at all; but then it breaks out from under the cloud again, and always makes farther advances in his race. So the child of God may be under a cloud; grace may be under a cloud and disappear, as if it was no grace at all; but then it breaks out again further advanced: for the man grows in grace and in the knowledge of the Lord Jesus Christ; hath more experience of the Lord’s pity and favour; more insight into the mysteries of the gospel.
Gospel purity inclines a man to make advances in religion. He forgets the things that are behind and presseth forward. He can never be pure enough: he goes from strength to strength. “The path of the just is as the shining light, that shineth more and more unto the perfect day.” It is true, there are ebbings and flowings of grace. The person may be going sometimes backward, at other times forward, but his ordinary course is like the sun: it may be under a cloud and out of view, as if there was no sun at all; but then it breaks out from under the cloud again, and always makes farther advances in his race. So the child of God may be under a cloud; grace may be under a cloud and disappear, as if it was no grace at all; but then it breaks out again further advanced: for the man grows in grace and in the knowledge of the Lord Jesus Christ; hath more experience of the Lord’s pity and favour; more insight into the mysteries of the gospel.
