In this verse the apostle first definitely indicates the cause of his anxiety, and the Epistle begins to assume a polemic tone. This verse is, therefore, the prelude of the impending attack on the false teachers (Colossians 2:8-23).
This I say, that no one may be deluding you in persuasive speech (Colossians 2:8, Colossians 2:18, Colossians 2:23; Ephesians 4:14; 1 Corinthians 2:1, 1 Corinthians 2:4,1 Corinthians 2:13; 1 Timothy 6:20; Psalms 55:21).
This was the danger which made a more adequate comprehension of Christianity so necessary to the Colossians (verses 2, 3). πιθανολογία, one of the numerous hapax logo-menu of this Epistle (words only used here in the New Testament), compounds into one word the πειθοῖ λόγοι ("persuasive words") of 1 Corinthians 2:4 (compare "word of wisdom," verse 23).
In classical writers it denotes plausible, ad captandum reasoning. παραλογίζομαι (only here and James 1:22 in the New Testament) is "to use bad logic," "to play off fallacies (paralogisms)." The new teachers were fluent, specious reasoners, and had a store of sophistical arguments at command.
The tense of the verb indicates an apprehension as to what may be now going on (1 Corinthians 2:8, 1 Corinthians 2:16, 18, 20; Colossians 1:23). We shall see afterwards (1 Corinthians 2:8 -23) what was the doctrine underlying this "persuasive speech."