Jamieson, Fausset and Brown on 1 Corinthians 2:3

3. I--the preacher: as 1Co 2:2 describes the subject, "Christ crucified," and 1Co 2:4 the mode of preaching: "my speech ... not with enticing words," "but in demonstration of the Spirit."

weakness--personal and bodily (2Co 10:10; 12:7, 9; Ga 4:13).

trembling--(compare Php 2:12). Not personal fear, but a trembling anxiety to perform a duty; anxious conscientiousness, as proved by the contrast to "eye service" (Ep 6:5) [Conybeare and Howson].