With the word brothers
(see also 1 Corinthians 14:6, 1 Corinthians 14:26, and 1 Corinthians 14:39) Paul expresses his love for and identification with the Corinthians. He wants them to become mature in their view and in their use of the spiritual gifts. He is probably thinking of God’s words to Jeremiah: “For my people are foolish; they know me not;
they are stupid children; they have no understanding. They are 'wise'— in doing evil! But how to do good they know not” (Jeremiah 4:22).
20 Brothers, do not be children in your thinking. Be infants in evil, but in your thinking be mature.