The discussion turned on work on the Sabbath. The Father's work in maintaining and redeeming the world has continued from the creation until the present moment (ἕως ἄρτι): until now, not interrupted by the Sabbath.
And I work (κἀγὼ ἐργάζομαι)
Or, I also work. The two clauses are coordinated. The relation, as Meyer observes, is not that of imitation, or example, but of equality of will and procedure. Jesus does not violate the divine ideal of the Sabbath by His holy activity on that day. “Man's true rest is not a rest from human, earthly labor, but a rest for divine, heavenly labor. Thus the merely negative, traditional observance of the Sabbath is placed in sharp contrast with the positive, final fulfillment of spiritual service, for which it was a preparation” (Westcott).