In this they were sealed; that is, they received testimony with the seal of the gifts of the Holy Spirit. Consequently, they received everything that Christianity gives, and therefore are equal in all things to Christians from the Jews.
What has been said gives the grounds for a positive decision on reception into Christianity. Faith in Christ, joined to a sincere desire to partake of the work of salvation accomplished by Him, is the first and necessary requirement of converts.
Everything else is the work of God's grace. St. John Chrysostom says: See how he everywhere makes the Gentiles equal with the Jews.
By faith alone, he says, they received the same thing. This brings shame upon the Jews, or rather, it can teach them too that faith alone is needed, and not works, the law, and circumcision.
For in saying this, the apostles wish not only to justify the Gentiles, but also to teach the Jews to abandon the law.
Formerly the law saved those who kept everything written in the law. But now the Lord's grace saves through faith, even without observance of the law.