John Donne sounds like a character in a Jack Vance book in this passage from his Essays in Divinity:
Picus, Earl of Mirandula, being a man of incontinent wit, and subject to the concupiscence of inaccessible knowledges and transcendencies, pursuing the rules of Cabal, out of the word Bresit, which is the title of this first book, by vexing and transposing and anagrammatizing the letters, hath expressed and wrung out this sum of Christian religion.
But let your study be rather to live according to that religion which you have, than to inquire into that from which God hath delivered you [he means Roman Catholicism]; for that is the looking back of Lot’s wife, and the distemper and distaste of the children of Israel, who remembered too much the Egyptian diet. If you will inquire whether any of the fathers of the primitive church did at any time pray for any of the dead, you shall be told (and truly) that Augustine did, that Ambrose did; but you shall not so presently be told how they deprehended [detected] themselves in an infirmity, and collected and corrected themselves ever when they were so praying. If you inquire whether any of them speak of purgatory, you shall easily find they do; but not so easily, in what sense; when they call the calamities of this life, or when they call the general conflagration of the world, purgatory. If you inquire after indulgences, you may find the name frequent amongst them; but not so easily find when and how the relaxations of penances publicly enjoined, were called indulgences: nor how, nor when, indulgences came to be applied to souls departed.
If thou enquire without a meliusinquirendum, without a thorough inquisition (which is not easy for any man who makes it not his whole study and profession) thou mayest come to think holy men have prayed for the dead, why may not I? Holy men speak of purgatory and indulgences, why should I abhor the names or the things? And so thou mayest fall into the first snare, it hath been done, therefore it may be done; and into another after, it may be done, therefore it must be done: when thou art come to think that some men are saved that have done it, thou wilt think that no man can be saved except he do it: from making infirmities excusable necessary (which is the bondage the council of Trent hath laid upon the world) to make problematical things, dogmatical; and matter of disputation, matter of faith;
Thou art bred in a reformed church, where the truth of Christ is sincerely preached, bless God for it; but even there thou mayest contract a pride, an opinion of purity, and uncharitably despise those who labor yet under their ignorances or superstitions; or thou mayest grow wary of they manna, and smell after Egyptian onions again. It is not enough that the state and the church hath destroyed idolatry so far as we said before; still there are weeds, still there are seeds: and therefore Care, take heed. But yet it is but, take heed. It is not take thought. Afflict not thyself, deject not thyself with ominous presages and prophetical melancholy, thy God will overthrow this religion and destroy this work which his right hand hath been a hundred years in repairing, and scatter his corn which his right hand hath been a hundred years in purifying. Come not to say, it was but the passion and animosity of Luther, it was but the ambition and singularity of Calvin that induced this religion, and now that that is spent, the religion melts like snow. Take no such thought, be not afraid that the truth of God shall or can perish: it is not, take thought, but it is much less, take arms.