Ulfila's theology shares with Arius its emphatic differentiation between the three Persons of the Trinity. Auxentius further reports his hostility to both of the above groups (i and ii) who wished to use language in '-ousios' ; both views, with others, Ulfila denounced as irreligious and Godless heresies, the work of Antichrists (§29). This is firmly in line with Auxentius' repeated insistence that Ulfila's teaching conformed with that of Christ and the evangelists as shown in the New Testament, and with 'tradition'. The New Testament never uses language involving '-ousios' when describing the relationship of Father and Son, and one of the main criticisms of both 'homousians' and 'homoeusians' was that their definitions were non-scriptural. Ulfila based his position entirely on Scripture, and Auxentius' account of it is liberal in its citations.The groups listed as (i) and (ii) are the homousians (led by Athanasius of Alexandria but also championed by the Cappadocian fathers: Basil of Caesarea, Gregory of Nazianzus, and Gregory of Nyssa) and the homoeusians (led by Basil of Ancyra).
Heather et al. provide a translation of The Letter of Auxentius, which was cited by the 5th century Arian theologian Maximinus, but includes a description of Ulfila. Two chaptering systems have arisen for the letter, and I'll be using the same citation system as the book does:
From chapter 26[44-45] (p. 138 of Heather et al.):
In accordance with tradition and the authority of the divine scriptures, he never concealed (the truth) that this God is in second place and the originator of all things from the Father and after the Father and on account of the Father and for the glory of the Father; and furthermore that he is great God and great Lord and great king and great mystery, great light [... c. 28 letters ...] Lord, provider and lawgiver, redeemer, saviour [... c. 50 letters ...] originator of [...], just judge judge of all the living and the dead, holding as greater (than himself) God his own Father [John 14.28] - this he always made clear according to the holy gospel.From chapter 28[47-48] (pp. 138-39 of Heather et al.):
He therefore strove to destroy the sect of homousians, because he held the persons of the divinity to be, not confused and mixed together, but discrete and distinct. The homoeusion too he rejected, because he defended not comparable things but different dispositions, and used to say that the Son is like his Father, not according to the erroneous depravity and perversity of the Macedonians that conflicts with the scriptures, but in accordance with the divine scriptures and tradition.From chapters 31-33[51-54] (pp. 139-40 of Heather et al.):
Now since there exists only one unbegotten God and there stands under him only one only-begotten God, the Holy Spirit our advocate can be called neither God nor Lord, but received its being from God through the Lord: neither originator nor creator, but illuminator, sanctifier, teacher and leader, helper and petitioner [... c. 15 letters] and confirmer, minister of Christ and distributor of acts of grace, the warrant of our inheritance, in whom we were 'sealed unto the day of redemption' [Eph. 4.30]. Without the Holy Spirit, none can say that Jesus is Lord, as the apostle says; 'No man can say, Jesus is Lord, except in the Holy Spirit' [I Cor. 12.3], and as Christ teaches; 'I am the way, and the truth, and the life: no one cometh unto the Father, but by me' [John 14.6]. And so they are Christians who in spirit and truth worship and glorify Christ [cf. John 4.23], and render thanks through Christ with love to God the Father.Obviously, we should not agree with Ulfila's errors, even while we recognize interesting parallels between his appeals to scripture and tradition and those of his opponents, as well as the claims of unique catholicity of those in agreement.
Steadfast in these and similar doctrines, flourishing gloriously for forty years in the bishopric, he preached unceasingly with apostolic grace in the Greek, Latin and Gothic languages, in the one and only church of Christ; for one is the church of the living God, 'the pillar and ground of the truth' [I Tim. 3.15]: asserting and bearing witness that there is but one flock of Christ our Lord and God, one worship and one edifice, one virgin and one bride, one queen and one vine, one house, one temple, one assembly of Christians, and that all other assemblies are not churches of God but 'synagogues of Satan' [Rev. 2.9, cf. 3.9].
And that all he said, and all I have set down, is from the divine Scriptures, 'let him that readeth understand' [Matt. 24.15]. He left behind him several tractates and many interpretations in these three languages for the benefit and edification of those willing to accept it, and as his own eternal memorial and recompense.