Open ye the gates, that the righteous nation which keepeth the truth may enter in. The righteous nation - The converted Gentiles shall have the gates opened - a full entrance into all the glories and privileges of the Gospel; being fellow heirs with the converted Jews. The Jewish peculiarity is destroyed, for the middle wall of partition is broken down.
The truth - The Gospel itself - as the fulfillment of all the ancient types, shadows, and ceremonies; and therefore termed the truth, in opposition to all those shadowy rites and ceremonies. "The law was given by Moses; but grace and Truth came by Jesus Christ; "Joh 1:17, and see the note there.