“Human learning, with the blessing of God upon it, introduces us to divine wisdom; and while we study the works of nature the God of nature will manifest himself to us; since, to a well-tutored mind, “The heavens,” without a miracle, “declare his glory, and the firmament showeth his handy-work.””

Source: Reason: The Only Oracle Of Man (1784), Ch. V Section II - Containing Observations on the Providence and Agency of God, as it Respects the Natural and Moral World, with Strictures on Revelation in General
Context: The idea of a God we infer from our experimental dependence on something superior to ourselves in wisdom, power and goodness, which we call God; our senses discover to us the works of God which we call nature, and which is a manifest demonstration of his invisible essence. Thus it is from the works of nature that we deduce the knowledge of a God, and not because we have, or can have any immediate knowledge of, or revelation from him.

Source: Reason: The Only Oracle Of Man (1784), Ch. V Section II - Containing Observations on the Providence and Agency of God, as it Respects the Natural and Moral World, with Strictures on Revelation in General

For sometimes it is good and easy, and sometimes it is hard and grievous. And in as much as it is good and easy it belongeth to the rightfulness; and in as much as it is hard and grievous our good Lord Jesus reformeth it by mercy and grace through the virtue of His blessed Passion, and so bringeth it to the rightfulness.
And though these two be thus accorded and oned, yet both shall be known in Heaven without end. The first doom, which is of God’s rightfulness, is of His high endless life; and this is that fair sweet doom that was shewed in all the fair Revelation, in which I saw Him assign to us no manner of blame. But though this was sweet and delectable, yet in the beholding only of this, I could not be fully eased: and that was because of the doom of Holy Church, which I had afore understood and which was continually in my sight. And therefore by this doom methought I understood that sinners are worthy sometime of blame and wrath; but these two could I not see in God; and therefore my desire was more than I can or may tell. For the higher doom was shewed by God Himself in that same time, and therefore me behoved needs to take it; and the lower doom was learned me afore in Holy Church, and therefore I might in no way leave the lower doom. Then was this my desire: that I might see in God in what manner that which the doom of Holy Church teacheth is true in His sight, and how it belongeth to me verily to know it; whereby the two dooms might both be saved, so as it were worshipful to God and right way to me.
And to all this I had none other answer but a marvellous example of a lord and of a servant, as I shall tell after: — and that full mistily shewed. And yet I stand desiring, and will unto my end, that I might by grace know these two dooms as it belongeth to me. For all heavenly, and all earthly things that belong to Heaven, are comprehended in these two dooms. And the more understanding, by the gracious leading of the Holy Ghost, that we have of these two dooms, the more we shall see and know our failings. And ever the more that we see them, the more, of nature, by grace, we shall long to be fulfilled of endless joy and bliss. For we are made thereto, and our Nature-Substance is now blissful in God, and hath been since it was made, and shall be without end.
Summations, Chapter 45

Source: Dictionary of Burning Words of Brilliant Writers (1895), P. 60.

1790s, The Age of Reason, Part I (1794)

Golden Sayings of Epictetus
Context: But God hath introduced Man to be a spectator of Himself and of His works; and not a spectator only, but also an interpreter of them. Wherefore it is a shame for man to begin and to leave off where the brutes do. Rather he should begin there, and leave off where Nature leaves off in us: and that is at contemplation, and understanding, and a manner of life that is in harmony with herself. See then that ye die not without being spectators of these things. (13).

Google search of the second sentence, in quotes, yields a trio of 2019 books alone, most (there and in following) attributing it to Kepler—e.g., see Prof Basden's 2019 work, [Foundations and Practice of Research: Adventures with Dooyeweerd's Philosophy, The Complex Activity of Research [§10—4.1 Less-Obvious Pistic Functioning in Research], Advances in Research Methods, Abingdon-on-Thames, UK, Taylor & Francis-Routledge, 1st, 9781138720688, https://www.amazon.com/Foundations-Practice-Research-Adventures-Dooyeweerds/dp/1138720682, February 25, 2020] (page 222).
While most citations of Kepler have been traced back to a translation of an original work, this quotation appears broadly without any such sourcing (e.g., Basden). Where it is sourced, the sources are either spurious (e.g., to the "New World Encyclopedia", a Paragon House/Unification Church product https://www.nytimes.com/1984/04/02/arts/unification-church-is-starting-a-publishing-house.html, wherein it is likewise unsourced), or to such sources as Henry Morris' 1988 creationist work, [Men of Science, Men of God: Great Scientists Who Believed the Bible, Green Forest, AR, Master Books, 21st reprint, 9780890510803, https://www.amazon.com/Men-Science-God-Henry-Morris/dp/0890510806, February 25, 2020] (page 21f).
Until a scholarly source is found that ties these statements to an original text from Kepler, they formally must be considered unattributed to Kepler.
Disputed quotes

Letter to Alexander Pope; compare: "Slave to no sect, who takes no private road, But looks through Nature up to Nature’s God", Alexander Pope, Essay on Man, epistle iv. line 331.

Source: Christ's Object Lessons (1900), Ch. 1, p. 25 - 26