This salvation (touto to sōtērion). Adjective from sōtēr (Saviour), saving, bringing salvation. Common in the old Greek. The neuter as here often in lxx (as Ps 67:2) as substantive like sōtēria (cf. Luk 3:6).
They will also hear (autoi kai akousontai). Autoi as opposed to the rejection by the Jews, “vivid and antithetical” (Page).