We can see how easily such variations could find their way into liturgical passages. R. Judah, when he was a guest at another s table, included in the grace after meals a passage similar to the one before us (Berachoth 46a).
Page 7. At all times let a man fear God (לְעוֺלָם). This is a liturgical exhortation to inward religiousness, and does not belong to the prayer proper. It is taken from the Tanna debe Eliyahu rabba (tenth century), chapter xxi, introducing the following prayers from Sovereign of all worlds (רִבּוֺן) to (P.B. page 9) I will bring back your captivity before your eyes saith the Lord (לְעֵינֵיכֶם אָמַר יְיָ). Some authorities hold that we should render " At all times let a man fear God secretly (בַּסֵּתֶר) as well as openly (וּבַגָּלוּי)," and that the reference is to periods of persecution when the open profession of Judaism was interdicted.
Sovereign of all worlds (רִבּוֺן). In this passage we have the true Rabbinic spirit on the subject of "grace" and "works." The Rabbis held that reward and punishment were meted out in some sort of accordance with a man's righteousness and sin. But nothing that man, with his small powers and finite opportunities, can do constitutes a claim on the favour of the All-mighty and the Infinite. In the final resort all that man receives from the divine hand is an act of grace. Hence: Not because of (i.e. relying on) our righteous acts do we lay our supplications before thee, but because of (or relying on) thine abundant mercies.
This passage is probably the prayer briefly referred to in the Talmud (Tractate Yoma 87 b), and was originally intended for the concluding service of the Day of Atonement, where it also finds a place (P.B. page 267). The Sephardim have a beautiful addition (ending with Isaiah xl. 15) to the paragraph which in P.B. (page 8) ends for all is vanity (Ecclesiastes iii. 19). It would run thus : and the preeminence of man over the beast is nought, for all is vanity, save only the pure soul which will hereafter render its judgment and account before the throne of thy glory. (לְבַד הַנְּשָׁמָה הַטְּהוֺרָה שֶׁהִיא עֲתִידָה לִתֵּן דִּין שְחֶשְׁבּוֹן לִפְנֵי כִסֵּא כְבוֹדֶךָ)