A.T. Robertson Commentary 2 Corinthians 12:18

"I exhorted Titus, and I sent the brother with him. Did Titus take any advantage of you? walked we not in the same spirit? [walked we] not in the same steps?" — 2 Corinthians 12:18 (ASV)

The brother (τον αδελφον). Probably the brother of Titus (cf. 8:18).

Did Titus take advantage of you? (μητ επλεονεκτησεν υμας Τιτοσ?). That puts the issue squarely.

By the same Spirit (τω αυτω πνευματ). That translation refers to the Holy Spirit and makes the case instrumental. The locative case, "in the same spirit," makes it mean that Paul's attitude is the same as that of Titus and most likely is correct, for "in the same steps" (τοις αυτοις ιχνεσιν) is in locative case.