Heidegger was a prominent Swiss reformed theologian, professor and the principal author of the Formula Consensus Helvetica (The Swiss Form of Consensus), 1675.
Body of Theology, or, Corpus Theologiae, 1700, Zurich
as quoted in Heinrich Heppe, Reformed Dogmatics, 1861, revised and edited by Ernst Bizer, English translation by G.T. Thompson, 1950, reprinted in 2007 by Wipf and Stock, p. 89 and 517
Consequently we answer the objection thus: that He wills not the death of the sinner by legislative will, so far as He seriously wills that there be an individual connection between the conversion of the sinner and his salvation. Whence He seriously invites certain men to conversion and to those who do seriously convert He promises life; although at the same time He does not will it by His decerning [from the Latin decernens, that is, decretive] will, or although He has not decreed from eternity to confer faith and repentance by grace upon all sinners and so actually to save them
Whether the serious is opposed to a joke, God in no way plays in the business of calling; or to pretence. He likewise does not simulate [pretend], because He does not profess one thing outwardly in words, concealing something else inwardly in his mind, but declares to men by calling his plain, open and steadfast will. And since the parts of calling are commands and promises, as often as He calls He commands and orders them seriously to repent and believe. For He wills that they repent and believe by his perceptive and approving will, although He does not will by His discerning will, effectual to the giving of faith and repentance. He has the right to demand both.—Moreover calling promises salvation, but not to anyone promiscuously or without condition, only to the believing and repentant person.
as quoted in Heppe, Reformed Dogmatics, p. 623. This quote was compiled by David Ponter.
Even in early times circumcision also conferred upon the circumcised among the non-elect a privilege above the non-circumcised. To them were entrusted the oracles of God, Rom. 3:1-2. By a like reasoning there is a common grace and favour of God which all baptized persons possess, even the non-elect, viz., initiation and engrafting into the outward body of the Church, in virtue of which even though perishing they have a right to the name of uieis basilasias [sons of the kingdom] and enjoy the outward privileges of God’s covenanted. But this is the mere courtyard, shell and surface of baptism.
The Formula Consensus Helvetica, 1675
See here for the full text. Johann Heidegger was the principle author of The Swiss Form of Consensus.
Likewise the external call itself, which is made by the preaching of the Gospel, is on the part of God also, who earnestly and sincerely calls. For in his Word He most earnestly and truly reveals, not, indeed, his secret will respecting the salvation or destruction of each individual, but our responsibility, and what will happen to us if we do or neglect this duty. Clearly it is the will of God who calls, that they who are called come to him and not neglect so great a salvation, and so he earnestly promises eternal life to those who come to him by faith; for, as the Apostle declares, “It is a trustworthy saying: For if we have died with Him, we shall also live with Him; if we disown Him, He will also disown us; if we are faithless, He will remain faithful, for He cannot disown Himself (2 Tim 2:12„13). Neither is this call without result for those who disobey; for God always accomplishes his will, even the demonstration of duty, and following this, either the salvation of the elect who fulfill their responsibility, or the inexcusableness of the rest who neglect the duty set before them. Certainly the spiritual man in no way determined the eternal purpose of God to produce faith along with the externally offered, or written Word of God. Moreover, because God approved every truth which flows from his counsel, it is correctly said to be his will, that everyone who sees the Son and believes in him may have everlasting life (John 6:40). Although these “all” are the elect alone, and God formed no plan of universal salvation without any selection of persons, and Christ therefore died not for everyone but only for the elect who were given to him; yet he intends this in any case to be universally true, which follows from his special and definite purpose. But that, by God’s will, the elect alone believe in the external call which is universally offered, while the reprobate are hardened. This proceeds solely from the discriminating grace of God; election by the same grace to those who believe, but their own native wickedness to the reprobate who remain in sin, who after their hardened and impenitent heart build up for themselves wrath for the Day of Judgment, and revelation of the righteous judgment of God
Heinrich Heppe Summarizing Heidegger
as quoted in Heinrich Heppe, Reformed Dogmatics, 1861, revised and edited by Ernst Bizer, English translation by G.T. Thompson, 1950, reprinted in 2007 by Wipf and Stock, p. 96. The block quote is Heppe’s. The parts in quotation marks are Heidegger’s. The context is God’s general relations to all of his creatures.
Since then God’s love for the creature is essentially a “love not due”, it appears as grace. “God’s grace is his virtue and perfection, by which He bestows and communicates Himself becomingly on and to the creature beyond all merit belonging to it” (Heidegger, Corpus Theologiae, 1700, Zurich, II, 94).