This powerful confession was penned by Gottschalk about AD 849-850 while he was in prison. Translation by Rev. Ronald Hanko published in the Protestant Reformed Theological Journal, vol. 12:1 (slightly edited).

I believe and also confess that although Thou hadst foreknown before the ages all things future, whether good or evil; that Thou hast predestinated only the good. The good, however, has been predestinated by Thee in two ways, yea from Thy revelation it is evident that it is so composed, that is, in benefits of grace and judgments of justice. Of this the Psalmist gives clearest proof: “Thou Lord lovest both mercy and judgment” (Ps. 33:5). And so Thou hast graciously predestinated life eternal for all Thy elect, and them, without any merit, to eternal glory. For it would have been in vain that Thou hadst predestinated life for them, unless Thou hadst also predestinated them for it.

So also in nearly the same way Thou hast predestinated lasting merited punishment for the devil and his angels, and for all reprobate men, as also Thou hast predestinated them for punishment. Undoubtedly it would have been without cause that Thou hadst predestinated them for the punishment of eternal death unless Thou hadst also predestinated them for it. For they would not go to it unless destined, neither would they have been destined unless predestined. Indeed, if even one of the reprobate (which is impossible) had been destined thither, who had not been predestinated, then Thou, Who before all ages hast been He Who is not able even for a moment to be changeable, shouldest have now have been shown to be changed.

Therefore, because Thou, Lord, alone art who Thou art (Ex. 3:4), even as Thou Thyself hast testified; and as David likewise says to Thee: “Thou Thyself art forever the same” (Ps. 102:27), and as another also says: “Thou art, Lord, and changest not” (Mal. 3:1); and as Thy distinguished preacher, Paul asserts: “Thou alone hast immortality” (I Tim. 6:16), that is, unchangeableness; “with whom” (and that is said of no one else by the Apostle) “is no variableness neither shadow of turning” ( James 1:17): from this it is manifest very clearly; and should be clear enough to anyone of sober wisdom, that Thou hast foreknown and predestinated already, before the ages, without any interval, at the same time and together, the whole as well as each one of Thy works. Indeed this parity is spoken of by Isaiah: “I have done those things which are yet to be” (Is. 45:1)….

And so it is with a view to the elect and reprobate, double predestination is called twofold; for while it is one, it is yet double, even as charity and love are frequently spoken of as double both by Augustine and by certain other fathers. For though they are not two but one, yet with a view to God and the neighbor are double. And thus when it is said by the father, Augustine, that the works of God are twofold, he clearly wishes to indicate double: and also that the world is said to be of four parts, and yet not four but one. And that a continent is made of five parts does not mean that he teaches that it is five, but one. Hence, also a double knowledge of the Jews is spoken of by holy Gregory and yet though it be double, it is known to be one….

Neither ought it be thought absurd by anyone reasonably and piously wise, if double predestination is believed and known and said without doubting to be a fact, like as Thou, our Lord, by nature art one, but at the same time art also personally triune: who certainly according to this Thy double predestination art good in blessing of some, just in punishing others (as Thy Augustine sincerely believes and faithfully asserts). And moreover, as he subsequently confesses, Thou art good in all things, seeing that it is good when a debt is paid; and just in all seeing that it is just when a debt is pardoned without defrauding anyone. All these things and also this (grace be to Thee) I both believe and confess according as Thou dost liberally grant Thy grace to me. And because by hard work, even by Thy grace, I find these things which Thou hast said expounded in Thy books and in the books of Thy ministers, so I dare not contradict that very perspicuous truth, since I am truly afraid of being denied by Thee as Thou has threatened; and also that off-repeated sentence of Paul I fear greatly: “If any preach to you any thing else than what ye have received, let him be accursed” (Gal. 1:8).