“You are the fools, not I — for I did dwell
With a deep thought, and with a softened eye,
On that Old Sexton's natural homily,
In which there was Obscurity and Fame,
The Glory and the Nothing of a Name.”

Stanzas 94–95 (tr. Richard Fanshawe); the Old Man of Restelo.
Epic poetry, Os Lusíadas (1572), Canto IV
Context: But an old man of venerable look
(Standing upon the shore amongst the crowds)
His eyes fixed upon us (on ship-board), shook
His head three times, overcast with sorrow's clouds:
And (straining his voice more, than well could brook
His aged lungs: it rattled in our shrouds)
Out of a science, practice did attest,
Let fly these words from an oraculous breast:O glory of commanding! O vain thirst
Of that same empty nothing we call fame!

"The Song of the Camp" (1856), in The Poetical Works of Bayard Taylor (1907), p. 86.

Source: Odd Thomas (2003), Chapter 1; Odd Thomas's introduction

Book III, line 522
De Arte Poetica (1527)

Source: The Stars My Destination

Book II
Exilius http://www.pierre-marteau.com/editions/1715-exilius.html (1715)

Source: What is Property? (1840), Ch. I: "Method Pursued in this Work. The Idea of a Revolution"
Context: Of what consequence to you, reader, is my obscure individuality? I live, like you, in a century in which reason submits only to fact and to evidence. My name, like yours, is truth-seeker. My mission is written in these words of the law: Speak without hatred and without fear; tell that which thou knowest! The work of our race is to build the temple of science, and this science includes man and Nature. Now, truth reveals itself to all; to-day to Newton and Pascal, tomorrow to the herdsman in the valley and the journeyman in the shop. Each one contributes his stone to the edifice; and, his task accomplished, disappears. Eternity precedes us, eternity follows us: between two infinites, of what account is one poor mortal that the century should inquire about him?
Disregard then, reader, my title and my character, and attend only to my arguments.

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