In De Testamento Bullinger concludes that the “holy patriarchs” (Enoch, Noah, Abraham, Isaac, Jacob, Joseph) were pleasing to God without the “ceremonies” (29a). In citing Galatians 3:16-17 he affirms, “Hence the patriarchs were saved by the blessing of the covenant, not of the law or of the ceremonies”. Significantly, Bullinger emphasizes at this point that the law which “originated later does not make void this covenant established earlier by God in Christ”.
Bullinger’s understanding is that because of the idolatry of Israel at the time of Moses so “it was pleasing to the wise and merciful Lord to come up and aid the collapsed covenant with certain props”. This is explained as follows, “God restored the main points of the ancient covenant, but unfolded it more fully, and inscribed it on tablets of stone with his own finger” (30a). That is to say, Bullinger understood that at the beginning the covenant was written on the hearts of the patriarchs but was codified in stone later on because of the covenant unfaithfulness of Israel. That is why, in his discussion of Genesis 17 earlier on, Bullinger makes this observation about “the record of the covenant”, viz “I should explain why there is no mention of legal records. Indeed, in place of such records are the words of Moses which we have already quoted, or, if you prefer more abundant words, the whole canonical Scripture” (6a). Bullinger’s assertion that the ‘conditions’ of the covenant were inscribed on the hearts of the patriarchs is directly alluded to in (45a): “The Lord did not bother to have any records written for the ancient patriarchs, for they bore the covenant in their hearts, inscribed by the finger of God”.
Bullinger further explains concerning the “ceremonies” in that “when they continued to be unfaithful and wicked, the burden of worthless ceremonies was thrown on their shoulders, ceremonies that the patriarchs did not have. Nevertheless, it is evident that the burden was imposed for an urgent reason, for this aim and with this plan, so that they would not introduce the worship of strange gods” (30a). In referring to the worship of God in Psalm 50 in this context, Bullinger employs some mental gymnastics to conclude, “Therefore, God instituted his own worship, and he declared that it was pleasing to him (Psalm 50), which he actually despised, so that, with this plan, he confirmed the covenant, and in addition to that he enveloped the mystery of Christ in these ceremonies as types”. In making this analysis Bullinger cites Tertullian, “For Tertullian, in his Against Marcion, book 2, says, ‘No one should blame God for the burden of the sacrifices, or the troublesome scrupulosities of the ceremonies, and oblations, as if he had desired such things for himself who clearly exclaimed, ‘What are the multitude of your sacrifices to me and who requires them from your hands?’ (Isaiah 1:11-12)’” (30b).
In Bullinger’s understanding, contrary to what he has to say about the “ceremonies”, he points out, “Now, therefore, in respect to the Decalogue and civil laws, no difference at all has arisen regarding the covenant and the people of God. For everywhere the love of God and the neighbour, faith and love maintain the mastery” (31a). In the same breath Bullinger underlines that “all the ceremonies were fulfilled by Christ, by whom alone it proclaims. Since they were types and shadows of eternal things, they become obsolete. So, that ancient religion, which was thriving in that golden age of the patriarchs before the law was brought forth, now flourishes throughout the entire world, renewed and restored more fully and more clearly by Christ and made perfect with a new people, namely, the Gentiles, as though a new light had been introduced into the world”. Bullinger firmly defends his view that it is not correct to “stigmatize…all the fathers preceding the coming of the Lord by the name of carnal Israel” because “antiquity also had the spiritual Israel”.
(see 'The One and Eternal Covenant of God' in An Everlasting Covenant: Biblical and Theological Essays in Honour of William J. Dumbrell (Reformed Theological Review Supplement Series #4, 2010) pp201-233)
See Steven Coxhead “Paul and the New Covenant Paradigm” in An Everlasting Covenant: Biblical and Theological Essays in Honour of William J. Dumbrell (Reformed Theological Review Supplement Series #4, 2010) pp119-144 for an interesting analysis which appears to have some parallels with Bullinger.