Why did Paul say he was not fit to be called an apostle?
His past persecution of the church disqualified him in his own estimation. He declared he was not meet to be called an apostle because he had persecuted the assembly of God—the early Jewish believers in Acts. He called himself the least of the apostles, acknowledging his unworthiness.
Les teaches that Paul described himself as the least of the apostles and not meet to be called an apostle because he persecuted the assembly of God. Les identifies that assembly as the early Jewish believers in Acts. Later, in Ephesians 3:8, Paul again calls himself less than the least of all saints. Les ties this to Jesus' words that the least in the kingdom of heaven is greater than John, indicating Paul is the one Jesus had in mind. Paul saw himself as unworthy because of that past persecution.