brothers: This was a common way to address each other (13:15, 26, 38; Genesis 27:29; Leviticus 10:6; 25:46; Numbers 20:3; Deuteronomy 1:28; 24:7; Joshua 22:3–4; 2 Samuel 2:26; Ezekiel 11:15).
in ignorance: See Acts 17:30; 1 Timothy 1:12–14. The Christian message challenges this lack of knowledge. The gospel calls everyone to respond with faith and to repent (Acts 2:38).