6. Which--the Holy Ghost.
      he shed--Greek, "poured out"; not only on the Church in general at Pentecost, but also "on us" individually. This pouring out of the Spirit comprehends the grace received before, in, and subsequently to, baptism.
      abundantly--Greek, "richly" (Col 3:16).
      through Jesus Christ--the channel and Mediator of the gift of the Holy Ghost.
      our Saviour--immediately; as the Father is mediately "our Saviour." The Father is the author of our salvation and saves us by Jesus Christ.

JFB.