From "Harmony of All the Religions Appointed by God" by Isaac Watts, 1674-1748
Holiness of heart and good works in life, where there is an opportunity for them, are insisted upon as necessary to our final salvation through all the Bible and perhaps in one or two places of the New Testament it is mentioned as necessary even to our justification as well as to our final salvation. Not that our best works of holiness are such a complete righteousness as to answer the present demands of God, under the gospel, but because they are necessary to show the truth of our faith and to render it a living justifying faith, which could not justify us if it were a dead faith or without works. It is a working faith that must justify us, as good works provide evidence for and prove the truth and life of our faith.
The apostle James argues this matter articulately in the last half of his second chapter, namely that works must be joined to our faith to make it a justifying faith. From all which it is plain, that in whatsoever scriptures faith is said to justify us without works, it can mean no more than this, namely that we are pardoned and accepted of God through our faith, trust or dependence on divine mercy and on the mediation of Christ, under a sense of the imperfection of our best works, and their insufficiency to answer the demands or any law for righteousness or justification. But still in other scriptures we are told, it must be such a faith as works by love, purifies the heart and, wheresoever there is opportunity, it produces the fruits of holiness in our lives and, therefore, good works in this sense are needful to secure our justification as well as they are very necessary, on many accounts, to honour God in this world, and to make us meet for final salvation. Thus the free grace of God in our justification is honoured and yet holiness is effectually secured in all them that are saved.
To conclude, let it be remembered, that since faith and repentance and holiness of heart and life are all necessary, for our salvation under the gospel, it is of infinitely more importance to see to it, that we pursue and practice this faith, repentance and holiness, than to be nicely and critically skilled in adjusting the logical relations of these Christian virtues to our salvation or our justification or in ranging them artificially in their proper place and order. The most skilful, most zealous and most orthodox person will certainly fall short of justification and salvation if these good qualities of faith and holiness are not found in him and the weakest in knowledge shall be justified and saved if these qualities and characters are found in them.