Last week we examined the remainder of Chapter 4 which ended in Paul addressing some of the Corinthians who were puffed up because they believed that he would not come to them -- he reasuures them that he will - if God wills it.
18 (AV) Now some are puffed up, as though I would not come to you.
18 ὡς μὴ ἐρχομένου δέ μου πρὸς ὑμᾶς ἐφυσιώθησάν τινες.
19 (AV) But I will come to you shortly, if the Lord will, and will know, not the speech of them which are puffed up, but the power.
19 ἐλεύσομαι δὲ ταχέως πρὸς ὑμᾶς, ἐὰν ὁ Κύριος θελήσῃ, καὶ γνώσομαι οὐ τὸν λόγον τῶν πεφυσιωμένων, ἀλλὰ τὴν δύναμιν.
"Shortly" is the adverb ταχέως from whose stem we get tachometer which measures how fast an engine runs. Paul is not interested in "the word" of the puffed up ones but the power. Paul the apostle has power to correct these who are "blown up", he wants action not words and he is prepared to use his apostolic powers to quell the rebellion if needed.
20 (AV) For the kingdom of God is not in word, but in power.
20 οὐ γὰρ ἐν λόγῳ ἡ βασιλεία τοῦ Θεοῦ, ἀλλ᾽ ἐν δυνάμει.
21 (AV) What will ye? shall I come unto you with a rod, or in love, and in the spirit of meekness?
21 τί θέλετε; ἐν ῥάβδῳ ἔλθω πρὸς ὑμᾶς, ἢ ἐν ἀγάπῃ πνεύματί τε πρᾳότητος; (1Co 4:15-21 TBT)
The kingdom of God is not in word but in power. The real rulership of the kingdom will be beyond the canniving and artful use of words from the mouths of those who are puffed up. The "rod" (r`a,bdoj, ou, h` rod, staff, stick) will be applied if needed and while not Paul's first choice he allows them to choose -- "what do you wish?", τί θέλετε;