Need Help on St. Ambrose and the Papacy

So I qouted St. Ambrose’s Commentaries on Twelve of David’s Psalms,

[40. 30] “It is to Peter himself that He says, 'You are Peter, and upon this rock I will build My Church [Mt 16: 18].” Where Peter is, there is the Church. And where the Church, no death is there, but life eternal."

A Protestant responded:
Your Catholic scholar Robert Eno notes that the quote you provide where Ambrose says ‘where Peter is, the Church is’: “… says nothing at all about papal authority.” - Robert Eno, the Rise of the Papacy, pp. 83-84

I dont know who Robert Eno is but I have heard this passage from St. Ambrose qouted by hundreds of highly educated Catholic Apologists, so can anyone provide more of the Commentaries on Twelve of Davids Psalms (the parts before and after it, so I can make sure I am in context) I cannot find the full work online anywhere.

Well, yes, this particular quote doesn’t actually mention papal “authority,” though clearly et sequitur.

Let’s look at another Ambrose quote:

[Christ] made answer: ‘You are Peter, and upon this rock will I build my Church’ Could he not, then, strengthen the faith of the man to whom, acting on his own authority, he gave the kingdom, whom he called the rock, thereby declaring him to be the foundation of the Church [Matt. 16:18]? (De Fide, 4:5 [A.D. 379]).

So you can’t have the Church without Peter, because Peter is the foundation of the Church, per Jesus Christ. And the best they can come up with is, “well, it doesn’t have the word ‘authority’ so how do we know that Jesus intended Peter to have authority?”

LAWYER: Your Honor, I object.
JUDGE: On what grounds?
LAWYER: On the grounds that it’s stupid.

But we need not look to Ambrose; we have it from Jesus himself:

To you I will give the KEYS to the Kingdom of Heaven (Matt 16:19).

BTW, keys = authority (as does the next passage about binding/loosing).

Oh, I found it in Latin. Hope you know Latin (I took one year in high school - this is way above my head). Unfortunately, it’s scanned text, so you can’t cut-and-paste into a translator. I suppose you could OCR it.

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