ISB ~ 1 Corinthians 2 v4

in demonstration of the Spirit:Even the most dynamic proclamations of the gospel remain ineffective unless the Spirit moves the minds and hearts of the listeners to accept it (Phil 1:29). Paul implies that his own modest speaking ability was a weakness that enabled God’s power to work more perfectly through him (2 Cor 12:9). The idea running throughout this passage is that God saves the world through what is foolish and weak so that he alone can be praised for the result (1 Cor 1:2129).

See word study:Unskilled at 2 Cor 11.