The question, "Surely not them, Lord?" is the thought challenged in this passage. Peter and those who were following Jesus were largely from a Jewish background and although Jesus had told his disciples that they would 'make disciples of all nations' (Matthew 28:19), and they hadn't realised that making them Jewish converts would not even factor into that equation. So a major shift in thinking was needed. Through God's help we can put aside our bias and tell the gospel to everyone, for God's good news is for all people and God's salvation is for all who put their trust in the Lord Jesus, who died on the cross for sinners like me and you and even 'them'.