The phrase occurs Eph 4:1; 1Th 2:12. Rev. gives the correct adverbial rendering worthily.
Unto all pleasing (εἰς πᾶσαν ἀρέσκειαν)
So as to please God in all ways. Compare 1Th 4:1, Ἁρέσκεια pleasing, only here in the New Testament. In classical Greek it has a bad sense, obsequiousness, cringing. Compare men-pleasers, Col 3:22.
In the knowledge (εἰς τὴν ἐπίγνωσιν)
Lit. unto the knowledge. The best texts read τῇ ἐπιγνώσει “by the knowledge:” by means of.