There is a thing that happens online constantly. Somebody wants to win an argument, so they go find a sentence from a saint, drop it in, and walk away. The sentence is usually real. The reading is usually garbage.
I have done it. You have probably done it. I want to give you a method that keeps you honest, because the Fathers deserve better than being used as ammunition, and because you will understand far more once you stop mining them.
1. Read the whole homily
This is the whole thing in one rule. Everything else is detail.
Here is why it matters. Open St. John Chrysostom's Homilies on the Gospel of John in the Fathers Library and look at how Homily XII opens. He begins by telling his congregation that he may have seemed needlessly hard on them the other day, that his language was too sharp, that he pushed his reproaches too far.
He is talking about the sermon he preached last time. To the same people. In the same room.
These are not essays. They are sermons, delivered in sequence, to a live congregation he knew by sight, and he is running an argument across weeks. He pushes hard one Sunday and eases off the next. He picks up a thread he dropped. He answers an objection somebody clearly made to him during the week.
Pull one sentence out of that and you have removed everything that told you how to read it. You would not do it to a friend's text messages. Do not do it to a saint's preaching.
2. Find out who he is arguing with
Almost every strong statement in patristic literature is aimed at somebody.
St. Athanasius writes the way he writes because of Arius. St. Irenaeus writes Against Heresies because of the Gnostics, and the title tells you so. St. Gregory of Nyssa writes Against Eunomius against a specific man with specific arguments.
When a Father presses a point extremely hard, he is usually pressing against something. If you do not know what he is pressing against, you will mistake a corrective for a complete statement. A doctor telling a starving man to eat is not issuing a universal rule that everyone should eat more.
So before you quote, ask: what is he attacking here? The work's own title will often tell you, and the opening paragraphs almost always will.
3. Know whose words you are actually reading
This one is specific and practical and I want you to take it seriously.
When you read patristic material in any edition, including this one, you are looking at layers. There is the Father's own text. There is a translator's English. There are editorial headings, summaries, and framing notes that a modern editor wrote to help you find your way.
Those editorial notes are useful. They are not the Father.
I will give you a live example. Working through the commentary attached to Scripture on this site, I came across this line filed under St. Irenaeus: "Irenaeus's recapitulation theology finds its fullest expression here. The Word descends so that man might ascend."
That is a true and helpful summary. It is also not a sentence St. Irenaeus wrote. It is an editor describing him. If you quoted it as Irenaeus, you would be putting modern words in a second century mouth, and somebody would eventually catch it.
This is why every commentary entry on this site links through to the full work. Not because the excerpt is dishonest, but because you should be able to go see the sentence sitting in its own paragraph before you build anything on it. If you cannot find the words in the actual text, do not attribute them.
4. One Father is not the Church
The Fathers are not a single author with one voice. They argue. They speculate. They occasionally get things wrong, and the Church knows it and says so.
What is authoritative is the consensus, what has been believed everywhere and always, not the private opinion of one man on one afternoon. A single Father speculating is a Father speculating. When you find something startling in one of them, the question is not "is this in a Father" but "is this what the Church holds."
This is also the answer to people who go digging for the weirdest sentence they can find in Origen or wherever and wave it around. Yes. And?
5. Let them read the Bible to you
Here is the part people skip, and it is the best part.
The Fathers are not primarily a doctrine delivery system. They are the greatest readers of Scripture the Church has ever produced, and most of what survives is them going through books of the Bible verse by verse in front of a congregation.
So use them that way. Open a chapter in the Bible, select a verse, and read what is attached to it in the Church Fathers section. Then follow the link into the whole work and read the surrounding pages.
Do that for a month and you will have learned more than by reading ten books about patristics.
6. Then apply it
I will stress this until the end of my days. The Gospel and the whole scholastic genre of theology means nothing to you if you do not apply it. If you learn math and never use it, it is just space occupying the mind. All education is for application.
The Fathers themselves would be the first to say it. They were bishops with hungry people outside the door. They were not writing so that you could win a thread.
Read the whole homily. Find out who he is fighting. Know whose words you are holding. Check it against the mind of the Church. And then go do something about it.