Why is v'acharei added in some siddurim?

Question

In the meditation after each Shmoneh Esrei, we read the line which includes the words בתורתך, מצותיך תרדוף. This comes from the prayer of Mar Brei D'ravina on Brachot 17a. But in my siddur Tefillah Hashalem (page 282), in the Shabbat Mincha davening, the word ואחרי is added before מצותיך .

It isn't added in any other davening that I have found in my siddur nor did I see it in the Koren or Artscrolls I had handy, but a quick look online reveals that this version appears in a variety of siddurim. What I didn't see was any explanation as to why in those other sources, the word is added. Is there another gemara text which has the meditation with it included? Is there a pasuk this is based on, or some other source for the prayer which is worded with acharei?

Answer 1

A quick search on the Bar Ilan Responsa Project gives exclusively Kabbalistic sources for this version (Veacharei Mitzvosecha) of the Tefillah prior to the modern-day Poskim (Teshuvos Vehanhagos and Yalkut Yosef).

Earlier sources include Seder Hayom of R. Moses b"r Judah ibn Machir (End of Kavanas Shemoneh Esrei Berachos), Shelah (Yoma, Perek Ner Mizvah 63 and Perek Derech Chaim Tochachas Mussar 204), and Sefer Charedim (Mitzvos Hateluyos Baaretz 5). Later sources include Nefesh Hachaim and Chida in Penei David. So I would go with some Kabbalistic source for this, although I don't what it is.

However, the quote from Shelah (see above, first source) also indicates that he had this Girsa in the Gemara, as he quotes the Tefillah from the Gemara, and uses this version. (But then in the second source he quotes the Tefillah directly from Sefer Charedim, so perhaps he just changed his Girsa based on what he had seen. Hard to tell.)

Either way, there seems to be evidence that this was first found in the early 1500s among Mekubalim, either added by them, or that a prominent Mekubal had such a Girsa in the Gemara.