That we should be to the praise of his glory, who first trusted in Christ.
All Commentaries on Ephesians 1:12 Go To Ephesians 1
Ambrosiaster
AD 400
What he means is that God first allotted the task of preaching to those believers in Christ who were from a Jewish background. Therefore no one of Gentile background was chosen to be an apostle. It was fitting that the first preachers should be chosen from those who had previously hoped for the salvation that had been promised to them in Christ.
