Edward Polhill had the advantage of writing late in the Puritan era. He is extremely well read and is able to cite a variety of previous doctors, as well as bring various positions together into harmony. He has much to say about double justification.
In his book A View of Some Divine Truths, he writes:
Thirdly, Obedience is necessary, though not to the first entrance into justification, yet to the continuance of it; not indeed as a cause, but as a condition. Thus Bishop Davenant, Bona opera sunt necessaria ad justificationis statum retinendum et conservandum; non ut causae, quae per se efficiant aut mereantur hanc conservationem; sed ut media seu conditiones, sine quibus Deus non vult justificationis gratiam in hominibus conservare. If a believer, who is instantly justified upon believing, would continue justified, he must sincerely obey God. Though his obedience in measure and degree reach not fully to the precept of the gospel; yet in truth and substance it comes up to the condition of it; else he cannot continue justified; this to me is very evident; we are at first justified by a living faith, such as virtually is obedience; and cannot continue justified by a dead one such as operates not at all. We are at first justified by a faith which accepts Christ as a Saviour and Lord; and cannot continue justified by such a faith as would divide Christ, taking his salvation from guilt, and by disobedience casting off his lordship; Continue reading