This is what it is to be one of Christ's little ones,—to be able to do what the Jews thought they could do, and could not; to have that within us through which we can do all things; to be possessed by His presence as our life, our strength, our merit, our hope, our crown; to become in a wonderful way His members, the instruments, or visible form, or sacramental sign, of the One Invisible Ever-Present Son of God, mystically reiterating in each of us all the acts of His earthly life, His birth, consecration, fasting, temptation, conflicts, victories, sufferings, agony, passion, death, resurrection, and ascension;—He being all in all,—we, with as little power in ourselves, as little excellence or merit, as the water in Baptism, or the bread and wine in Holy Communion; yet strong in the Lord and in the power of His might. - John Henry Newman (Plain & Parochial Seromns, Vol 6, Sermon 1)
It's typical to find in Newman's work elements which prefigure contemporary theology - we might compare the above to Vatican II's insight of the Church as Sacrament.
To my mind, Newman is one of the giants of Catholicism and I pray that I'll see him raised to the altars and subsequently proclaimed a Doctor of the Church.
Where lies Newman's greatness? Normally this would provoke an interminable monologue, but I'll just mention a few points.
1. His theory on the development of doctrine (originally published in his 1845 Essay on Development has not yet been superceded.
2. His intellectual and spiritual biography, Apologia pro Vita Sua is one of the few masterpieces which can worthily be compared to St. Augustine's Confessio.
3. His passion for the truth provided us with some of the greatest controversial, spiritual and theological writing of the past 300 years.
4. His integrity, despite attacks from within and outside the church, make him a fitting patron for Catholic scholars who diligently and responsably hold and defend their faith.