He became bishop of Milan in A.D. 374, after he gave up a successful political career.
In his work Of the Holy Spirit he wrote, “You see the Father and Christ also set teachers in the churches, and as the Father gives the gift of healings, so too does the Son give; as the father gives the gift of tongues, so too has the Son also granted it. In like manner we have heard also above concerning the Holy Spirit that He too grants the same kinds of graces. So, then, the Spirit gives the same gifts as the Father and the Son also gives them.10
10. Ambrose, Of the Spirit, vol. 10 Nicene and Post-Nicene Fathers of the Christian Church, 134.