Good works.

Herman Witsius has written:

“Mean while, in this respect too, there will be room for mentioning good works, for they shall be produced, 1st. As proofs of faith, of the union of believers with Christ, of their adoption, and of that holiness, without which none can see God, and of friendship with God, and brotherhood with Christ. 2dly. As signs of that sacred hunger and thirst, with which they desired happiness, and of that strenuous endeavor, by which, not regarding the advantage of this life, and despising carnal pleasure, they had sought the kingdom of heaven and its righteousness; and it is inconsistent with the perfection of the infinitely holy God, to disappoint this hunger and thirst, and seeking after his kingdom. 3dly. As effects of divine grace, to which, the communication of divine glory will answer, in the most wise proportion, when it shall come to crown his own gifts. For the more abundant measure of sanctification any one has obtained in this life, and the more he has gained by the talent entrusted to him, it is also credible, that the portion of glory will be the more exuberant, which the divine bounty hath appointed for him. And in this sense, we imagine, it is so often said in scripture, that every one shall be recompensed according to his works, not that these works are, on any account, the cause of any right they will have, to claim the reward; but as they are evidences of our adoption and of our seeking the chief good, and as they shew that proportion of grace, according to which the proportion of future glory will be dispensed.”

(Witsius, Herman. The Economy of the Covenants Between God and Man, Volume I, Kingsburg, CA: den Dulk Christian Foundation, 1990, p. 419)