Inspired by S, I have decided to post a contest. The object is to guess which individual or sect wrote the following text in the past 3000 years (The possible answers include secterian and apochriphal or pseudepigraphal sources as well).
Prize: A virtual pat on the back
לַמְנַצֵחַ בִּנְגִינוֹת מִזְמוֹר שִׁיר׃ מִי יְסַפֵּר תְּהִלָּתְךָ יְיָ. יַגִּיד חַסְדְּךָ לְדוֹר וָדוֹר׃ כִּי גָדַלְתָּ עַד מְאֹד אֱלֹהֵינוּ. נוֹרָא אַתָּה בְּכָל הָאָרֶץ׃ וַאֲנַחְנוּ עֲבָדֶיךָ יְיָ עֲשִׂיתָנוּ. נְסַפֵּר אֲמִתְּךָ לְעוֹלָם וָעֶד ׃ בְּמַקְהֵלוֹת נְבָרְכֶךָ. נַזְכִּיר שִׁמְךָ לְעוֹלָם כִּי רַב הוּא. אֲשֶׁר עָלֵינוּ גַּאֲוָתְךָ מֵעוֹלָם. תִּתְפָּאַר בְּעַמְּךָ לְדוֹר דּוֹרִים׃ זֶרַע עֲבָדֶיךָ יִכּוֹן לְפָנֶיךָ לְהַגִּיד חַסְדְּךָ יְיָ יוֹם יוֹם׃
[UPDATE: The answer is … drumroll please … The Ramchal! (go adderabbi) he wrote a full sefer tehillim (with 150 chapters) before he was 20 (and before he started writing the kabblah that the maggid revealed to him). The whole sefer was locked in the same box as the maggid manuscripts after the cherem and the box was lost. 8 chapters remain, however, since some of his friends made copies of them. This one is part of a liturgy he composed for simchat Torah where one chapter was recited at the end of every hakafah. The one I posted was the chapter from the second hakafah.]
