Nowadays, that usage is rare enough that it sounds old-fashioned; the usage borders on archaic. I notice that usage about once or twice a year. But one of the best-known sentences in Western civiliation:

For God so loved the world that he gave his only begotten son... (King James Bible, 1611)

There's something odd about it not being used. It is well-known that there are exactly seven coordinating conjunctions and there is a well-known mnemonic of FANBOYS, and the F stands for for. So it's in a very exclusive club, these words are at the center of grammar, and it's hard to get into -- plus and then should be allowed into the club, but no one adds them.

And apparently it's difficult to get out of the club. So we have this strange usage of for, enshrined in grammar, enshrined in some of the most famous literature in our culture, and yet buried in the past and rarely used today.

Shakespeare used for:

Neither a borrower nor a lender be, for loan oft loses both itself and friend; (Shakespeare, Hamlet, 1601)

For he's a jolly good fellow (around mid-1700's)

What Does For Mean?

Come swim like a fish or you'll sink like a stone, for the times they are a-changin;

There is a very interesting problem with saying that for means because.

Blessed are the meek, for they shall inherit the earth.

And most of the old uses are like that.

But the angel said to them, "Do not be afraid! For behold, I bring you good news of great joy that will be for all the people.

Let me try to put that into English. The scientifc revolution started in the early 1600's, and it was accompanied by a change in how people thought of causation. Our modern word because fits this scientific understand.

It's really hard to crawl inside the mind of a 1600 Englishman who did not have that concept of causation. My current guess is this. The world was created by God, and exists the way it does because of God. There is no causation. But things did fit together in a logical way. So, 'the meek are blessed' is consistent with them 'inheriting the earth'. And vice versa.

In modern terms, this would give for the meaning 'and we know this is true because.' Or, 'as a sign this is true . . ." But I do think it's more like both things existing together in the world as a sign of God's one decision.

So, to the extent that Hulsit is right, the 1600 meaning of for, as a coorinating conjunction, could not be our modern understanding of the word because, because they did not have that understanding.

But, if I am reading this right, the 1600 notion of causality has partially survived in our language, in the meaning of the word for. The evidence for this is thin. I see those Bible versus as changing meaning when for is replaced with because. I had the feeling that MW was not completely happy with because as a definition for for. And the NIV version of the bible, which attempted to translate the bible into modern English, left for intact.

It is not impossible that this meaning has survived -- assuming we understand the bible where for is used.

Also, it is not clear why for can stand alone at the start of a sentence if it meant because. From Hamlet:

We do it wrong, being so majestical,
To offer it the show of violence;
For it is, as the air, invulnerable,
And our vain blows malicious mockery.

But break my heart,—For I must hold my tongue!

For he himself is subject to his birth:

For the apparel oft proclaims the man;

Swift

I lay down on the grass, which was very short and soft, where I slept sounder than ever I remembered to have done in my life, and, as I reckoned, about nine hours; for when I awaked, it was just day-light

I drank it off at a draught, which I might well do, for it did not hold half a pint,

It appeared that he understood me well enough, for he shook his head by way of disapprobation

Here the emperor ascended, with many principal lords of his court, to have an opportunity of viewing me, as I was told, for I could not see them.

Suppose that's true. Then before that time, when people used the words cause, because, and for, they did not mean our modern scientific notion, because they didn't have that.

That usage which is how it's almost always used nowadays. But this webpage is about for as a coordinating conjunction.

For God so loved the world that he gave his only begotten son

For he's a jolly good fellow

Blessed are the meek, for they shall inherit the earth.

Meaning Because?

For the times, they are a-changin' (Dylan)
Because the times, they are a-changin
Cos the times, they are a-changin'

There is no question that for cannot always be subsitituted for because.

Why did you eat dinner? Because I was hungry.
Why did you eat dinner? For I was hungry.

For he's a jolly good fellow
Because he's a jolly good fellow.

But the lyrics of that song are translated from French. So it's questionable as an example, even though it's the only example I know of (for that particular problem). In the following, because cannot be substituted for for because of the behold.

But the angel said to them, "Do not be afraid! For behold, I bring you good news of great joy that will be for all the people. But the angel said to them, "Do not be afraid! Because behold, I bring you good news of great joy that will be for all the people.

But that could just be a grammatical thing.

Because John didn't come to the meeting, we didn't have a quorum.
For John didn't come to the meeting, we didn't have a quorum.

And Noah went in, and his sons, and his wife, and his sons' wives with him, into the ark, because of the waters of the flood.

Ideas of Causation

Let me try to put that into English. The scientifc revolution started in the early 1600's, and it was accompanied by a change in how people thought of causation. The religious notion, roughly, is that all things happen according to God's will. The scientific notion is to focus on events in the world causing other events.

Suppose that's true. Then before that time, when people used the words cause, because, and for, they did not mean our modern scientific notion, because they didn't have that.

There's a lot to discuss on that.

First, the word for was in use in the olden times, and because was rare. For example, the word because occurs once in Hamlet and once in Othello. It's in my last book 151 times. Meanwhile, for was common as a coordinating conjunction in the Bible and in Shakespeare, but not in modern writing.

So, those people who want to understand how ideas change should be drooling over the use of the word for. Um, I pretty much have a monopoly.

That cuts both ways! When people today use the words cause, because, and for, they probably don't mean the old notion, they mean the scientific notion. But I suspect that the 2021 meaning of for is influenced by the old notion of causality, I think that might be true.

And the third issue is what that pre-scientific notion of for was.

The Causality of For

Blessed are the meek, for they shall inherit the earth.

When you look at the Bible, and try to replace for with because, it's not exactly clear what is causing what. Consider this:

And, behold, there was a man in Jerusalem, whose name was Simeon; and the same man was just and devout, waiting for the consolation of Israel: and the Holy Ghost was upon him. And it was revealed unto him by the Holy Ghost, that he should not see death, before he had seen the Lord's Christ. And he came by the Spirit into the temple: and when the parents brought in the child Jesus, to do for him after the custom of the law. Then took he him up in his arms, and blessed God, and said,

Lord, now lettest thou thy servant depart in peace, according to thy word:

For mine eyes have seen thy salvation,

And even when we look at Dylan:

Come swim like a fish or you'll sink like a stone, for the times they are a-changin;
Come swim like a fish or you'll sink like a stone, because the times they are a-changin;
Because the times are changing, you will sink like a stone if you don't swim like a fish
Because the times are changing, you should swim like a fish instead of sinking like a stone.

The Don't-Make-a-Big-Deal Idea