Kevin DeYoung gives a short account of Pictet’s importance here.
The text below is from Pictet’s work, Christian Theology (Bk. 8, Ch. 6,7). Pictet describes the relationship between justification and sanctification.
This sanctification differs from justification in several respects: and they are expressly distinguished in scripture; thus (1 Cor. vi. 11,) “Ye are washed, ye are justified, ye are sanctified.” Justification delivers us from the guilt, sanctification from the filth, of sin; justification consists in the remission of sins through the righteousness of Christ imputed; sanctification is the renewal of the soul, and is inherent in us; justification is perfect, and is equal in all that are justified ; sanctification is imperfect, is bestowed in an unequal measure, and is gradually increased in every believer “according to the measure of the gift of Christ.” But although these benefits are distinct, yet are they never separated; hence they are often designated in scripture by one and the same word, “There is forgiveness with thee, that thou mayest be feared,” (Psalm cxxx. 4.) ” The Lamb of God” is said “to take away the sin of the world,” (John i. 29,) i. e. he takes it away by removing the curse, and washing away the stain. God has joined these two blessings together in the covenant of grace, in which he promises that “he will be merciful to the unrighteousness or sins of his people,” and that “he will write his law in their hearts.” (Jer. xxxi. 33, 34 ; Heb. viii. 10–12; x. 16.).
Nor does the nature of the case allow it to be otherwise; for the justice of God cannot permit him to adopt into his family, and bestow a title to eternal life upon any of our race, without at the same time stamping his own image upon them: since there can be no fellowship of light with darkness, and “without holiness no man shall see the Lord,” (Heb. xii. 14,) nor can any “partake of the inheritance of the saints in light,” unless first “made meet for it.” (Col. i. 12.) Christ is not only “made unto us righteousness,” but also “sanctification;” (I Cor. i. 30 ;) he is not only our surety, who has made satisfaction for us, but also our head, who makes us holy by the communications of his grace; his death, which is the propitiation for our sins, furnishes us with numerous motives to holiness; by showing us the heinousness of sin, God’s hatred of it, the unspeakable love of Christ, and the property which he has acquired in us by that death. (Rom. xiv. 8, 9 ; 1 Cor. vi. 19, 20; 2 Cor. v. 14, 15; Titus ii. 14 ; 1 Peter ii. 24.). The gospel which reveals to us the good tidings of forgiveness, also urges us to holiness, as a law, commanding us to “deny ungodliness and worldly lusts, and to live soberly, righteously, and godly, in this present world.” (Titus ii. 11, 12). The Spirit which is given us, is also a “spirit of holiness,” as well as a ” spirit of adoption ;” the faith which justifies us, “purifieth the heart,” (Acts xv. 9,) the baptism, which is administered “for the remission of sins,” is called “the washing of regeneration,” (Titus iii. 5,) and if in the Lord’s Supper the body of Christ broken, and the blood of Christ, shed, for sin, are exhibited to our eyes for the remission of our sins, they are also exhibited, as the nourishment of that spiritual life, which consists of sanctification.
As to the necessity of good works, it is clearly established from the express commands of God, from the necessity of our worshipping and serving God, from the nature of the covenant of grace, in which God promises every kind of blessing, but at the same time requires obedience, from the favors received at his hands, which are so many motives to good works, from the future glory which is promised, and to which good works stand related, as the means to the end, as the road to the goal, as seed-time to the harvest, as first fruits to the whole gathering, and as the contest to the victory, and from the necessity of consulting the advantage of our neighbors, and of “making our calling and election sure,” (which is done by good works.) These good works are performed by believers, and although they are not perfect, yet they may be truly called good, because they are wrought by the special influence of the Holy Spirit in their hearts, and by the assistance of God’s grace; hence they please God, who promises them a reward.
But although they are good, they are not meritorious, or deserving of eternal life. This is evident from four considerations. First, a work, to be meritorious, must be our own, for no one can be said to deserve aught for what belongs to another; but good works are the gifts of grace, and the fruits of the Spirit, and there is no one who must not adopt Paul’s language, “By the grace of God, I am what I am.” (1 Cor. xv. 10.) Secondly, a meritorious work must be one that is not due, for no one can have any merit in paying what he owes; but good works are due; “When ye shall have done all those things which are commanded you, say. We are unprofitable servants: we have done that which it was our duty to do,” (Luke xvii. 10.) Thirdly, there must be a proportion, not only between him who deserves, and him from whom it is deserved, but also between the good
work and the promised reward; but there is no proportion between the two in the present case ; not even when the good work is martyrdom, the most excellent of all. For (all) “the sufferings of this present time are
not worthy to be compared with the glory which shall be revealed,” (Rom. viii. 18.) Fourthly, a meritorious good work must be perfect; for where there is sin, there cannot be merit; but our works are imperfect, and are therefore compared to” filthy rags,” (Isaiah Ixiv. 6).
We saw a similar necessity of holiness in Robert Traill, in Owen, Rutherford, and Buchanan, and in JC Ryle, and we saw holiness and good works as the “way” or “road” to eternal life, though not the meritorious cause of it, in Davenant and Witsius.
So far the span of agreement on the necessity of holiness and holiness as the “way” to eternal life includes Puritan, Anglican (e.g., Davenant), and continental Reformed theologians.