הוּא-עָשָׂנוּ וְלֹא אֲנַחְנוּ is the Masoretic Ketiv text of Ps. 100: 3, while the Qere text is הוּא-עָשָׂנוּ וְלוֹ אֲנַחְנוּ. The Ketiv text (which is difficilior, it seems) is supported by the LXX: αυτος εποιησεν ημας και ουχ ημεις·
I want to draw your attention to two possible allusions to the verse in Christian writings. One of them to the Ketiv text, the other to Qere. Interesting enough both seem to address the relationship between Father and Son.
Qere: 1 Cor. 8:6 αλλ ημιν εις Θεος ο πατηρ, εξ ου τα παντα και ημεις εις αυτον ( וְלוֹ אֲנַחְנוּ), και εις Κυριος Ιησους Χριστος, δι ου τα παντα και ημεις δι αυτου.
Ketiv: Odes of Solomon 7: 12 (Translation of Charlesworth) "He has allowed Him to appear to them that are His own; in order that they may recognize Him that made them, and not suppose that they came of themselves (וְלֹא אֲנַחְנוּ )."
I was tempted to read in the Odes passage an allusion to both Ketiv ("they came [not] of themselves") and Qere ("that are His own"), but this second phrase may represent עַמּוֹ rather than וְלוֹ אֲנַחְנוּ.
Sorry I couldn't find a Syriac font to get the transmitted text of the Odes on the screen. (PJW may know a solution?)