The history of the supposed credo of Karaism

Sometimes when I come across something particularly interesting, I jot a note down for myself. Here's something I found, but I don't remember where I read it, so sorry to whomever I stole the thought from.

A cardinal principle of early Karaism (and perhaps a popular saying among Karaites still, although I am unsure of that) is the following, which is attributed to Anan ben David, possibly a seminal figure in the founding of Karaism, but certainly a seminal figure in Karaism in general.

His saying is as follows:

חפישו באורייתא שפיר ואל תשענו על דעתי
"Search diligently in the Torah and don't rely on my opinion."

This credo really sums up the Karaite attitude toward Scripture. Independence of interpretation being seen as a desirable thing, even as it informs practical halakhic practice.

Someone pointed out that the first half is in Aramaic, while the second half is in Hebrew. Thus it would seem plausible that the second half is actually a gloss on the first. Perhaps Anan did say "Search diligently in the Torah," but perhaps someone else said "and don't rely on my opinion."