Lest Satan should get an advantage of us (ἵνα μὴ πλεονεκτηθῶμεν ὑπὸ τοῦ Σατανᾶ)
Lit., in order that we be not made gain of, or overreached, by Satan. Rev., that no advantage may be gained over us. The verb, from πλέον more, and ἔχω to have, appears in the noun πλεονεξία greed of gain, covetousness. See on Rom 1:29.
Are ignorant - devices (ἀγνοοῦμεν - νοήματα)
A paronomasia (see on Rom 1:29-31). As nearly as possible, “not know his knowing plots.”