Ki Eshmera Shabbat, by R’ Abraham ibn Ezra, as printed in the Vilna Edition of the Karaite Prayer Book (Vol. IV)
Virtually, every Karaite respects Rabbi Abraham ibn Ezra. He lived in the 12th Century, and he is arguably the greatest of the classical Rabbanite peshatist (plain meaning) commentators. I have even quoted him in my talks. One of the reasons he is such a good peshatist is because he was combatting the then-thriving Karaite movement, which espoused peshat above all.
In addition to writing commentaries, ibn Ezra also penned numerous poems – the most famous of which is Ki Eshmera Shabbat. It is well known that the poem wound up in Karaite prayer books. It is less well-known that the Karaites modified the poem to remove anti-Karaite rhetoric. And it is even less well-known that the version that appears in Karaite prayer book still appears to have anti-Karaite polemics.
