Who Killed Goliath?

So the ESV says two different people killed Goliath. Upon research, the prominent answer I find is that the copyist made a mistake in copying the Bible, and the other manuscript copiers followed. If that's true, that would make the Bible fallible. There has to be a better explanation. Please help. Thank you.

http://www.aomin.org/aoblog/2015/01/08/a-wide-ranging-important-jumbo-sized-dividing-line/
I do not remember the entirety of it but, watch or listen.

1. While I am trying to grow in patience, I confess that I still have zero, zip, none in regards to the hubris of critical scholars. On the one hand they claim that the redactionists did a masterful job, and yet we're supposed to believe that centuries worth of scribes - who (according to them) felt free to redact and correct the text - managed to overlook glaring contradictions that weren't noticed until modern liberal scholars identified them. Give me a break.

2. There are several years between 1 Sam 17 and 2 Sam 21. Celebrities and heroes tend to be honored in their cultures by having subsequent people named after them. The fact that there is a clear gap in time of many years should make it obvious that the Goliath of 1 Sam 17 was such a celebrity that his name was given to the person named Goliath in 2 Sam 21. I'm not sure how names were given in Philistine culture, but my guess is that as a baby or young boy, or perhaps at the time he became a man, his size, strength, and/or prowess in combat led whoever named him to assign that name to him.

I'm assuming the passages in question, because nothing is given in the OP.

1Chr.20:5 is parallel to 2Sam.21:19. It gives not only the term "brother" (of Goliath) but another name for that brother, Lahmi.

My operating assumption is that the Chronicler is offering clarity, to remove (for a later, less sophisticated (?) readership) any ambiguity over who killed the Goliath, 1Sam.17:4,51, of David's battle.

It's hard to imagine one who had read or heard the books of Samuel up through 2Sam.21 being unutterably confused by the commentary in ch.21 over the mighty-men of David. Wouldn't it be reasonable to think, "this fellow most likely was a relative of the other guy," if you knew the prior story?

I have to say, the intent of the author at 2Sam.21 appears to intentionally resurrect the memory of David's encounter. Here's another guy who handled yet another Goliath the way his king did. Almost, as if we are supposed to realize that when we have faith in our King, we may be called to follow him as a pattern, Jn.14:12.

Or, we could just read the Bible like BartEhrman.

At Sunday School we used to sing:

Only a boy named David
Only a little sling
Only a boy named David
But he could pray and sing
Only a boy named David
Only a rippling brook
Only a boy named David
But five little stones he took.

And one little stone went in the sling
And the sling went round and round
And one little stone went in the sling
And the sling went round and round
And round and round
And round and round
And round and round and round
And one little stone went up in the air
And the giant came tumbling down.

Problem solved

1Ch 20:5 And there was again war with the Philistines, and Elhanan the son of Jair struck down Lahmi the brother of Goliath the Gittite, the shaft of whose spear was like a weaver's beam.

2Sa 21:19 And there was again war with the Philistines at Gob, and Elhanan the son of Jaare-oregim, the Bethlehemite, struck down Goliath the Gittite, the shaft of whose spear was like a weaver's beam.

So who was struck down here, Goliath or Lahmi?

You have more information with the second text. The man's personal name/identifier was probably the Lahmi-moniker

The giants of Gath (we're given to know two of them) might both have had the name Goliath, maybe it was a family name; or as Ben said, maybe it was someone named for the former.

In real life, the are all sorts of little facts like this that require figuring out. Only in fairy tales and other fiction, do the authors remove all such eventualities, so there aren't any oddities making the story confusing. Like two big guys from the same town who are "likes-to-fight-guy," oh yea, with the same first or last name.

I've heard the suggestion that "Goliath" might have been a title or a military nickname given to the force's designated champion, or to warrior giants. Then it would be like a present-day naval fighter squadron reporting that "Cag" got shot down. The squadron commander is always called "Cag," Commander of the Air Group.

That's one of a handful of plausible explanations. What is not plausible, if you believe Scripture to be true, is the suggestion that maybe David didn't actually kill a giant at all. 1 Samuel 17 is clear that he did.