25 Here perhaps some one may ask, “whether the Holy Ghost only forgives sins, and not the Father and the Son also?” I answer, Both the Father and the Son forgive them. For the Son Himself says of the Father, “If you forgive men their trespasses, your heavenly Father will also forgive you.” And we say to Him in the Lord's Prayer, “Our Father, which art in heaven.” And among the other petitions we ask this, saying, “Forgive us our debts.” And again of Himself He says, “That ye may know that the Son of Man has power on earth to forgive sins.” “If then,” you will say, “The Father, the Son, and the Holy Spirit forgive sins, why is that impenitence which shall never be forgiven, said to relate only to the blasphemy of the Spirit, as though he who should be bound in this sin of impenitence should seem to resist the gift of the Holy Spirit, because by that gift is wrought the remission of sins?”
Now on this point, I will also ask, Whether Christ only cast out devils, or the Father and the Holy Spirit also? For if Christ only, what means His saying, “The Father that dwells in Me, He does the works.” For so it is said, “He does the works,” as if the Son does them not, but the Father who dwells in the Son. Why then in another place does He say, “My Father works hitherto, and I work.” And a little after, “For what things soever He does, these also does the Son likewise.” But when in another place He says, “If I had not done among them the works which none other man did,” He speaks as if He did them alone.
Now if these things are so expressed, as that nevertheless the works of the Father and the Son are inseparable, what must we believe of the Holy Spirit, but that He also works equally with them? For in that very place, from which this question arose which we are discussing, when the Son was casting out devils, He yet said, “If I in the Holy Spirit cast out devils, then the kingdom of God has come unto you.”
Source: Sermons on Selected Lessons of the New Testament (New Advent)