Augustine was not a biblical Christian, but a Roman Catholic monk.

In his writings outside of his speculations on predestination, St. Augustine was generally reflecting the catholic consensus of the time, and the beliefs which he held as the catholic bishop of Hippo in North Africa. Here are some of the catholic beliefs of Aurelius Augustine, catholic Bishop of Hippo:

1. The canon of Scripture includes the Septuagint OT canon (deuterocanonicals, Apocrypha)

2. Authoritative Tradition

3. Baptismal regeneration and grace

4. Necessity of baptism for salvation

5. Real presence of Christ in the Eucharist (Lord's Supper)

6. The Mass is a sacrifice

7. Necessity of the Lord's Supper for salvation

8. Purgatory and praying for the departed

9. The communion of saints and saintly intercession

10. Authority of the Catholic Church

11. Apostolic Succession

12. Possibility of falling from grace

13. The sacrament of penance

14. Mary was ever virgin

~ Source (more in the article with statements and sources cited).