If Isaiah was the greatest prophet in Israelite history from David to the exile, why are his character and personal life not known to us? Same with Obadiah, Joel, Nahum who are obscure figures.
I can tell you have been hearing from Muslim critics, as this is the latest “fad” criticism of the Bible from Muslim critics. A couple of points on this. First of all, to pick on Isaiah is a clear error because we know quite a bit about Isaiah. This charge is simply not even true! We know where Isaiah lived. He lived in Jerusalem. We know within a couple of years when he was born and when he died. He was born around 765 BC and died around 695 BC. We know what he did for a living. He was a priest. We know the name of his father, which was Amoz. We know that as a young man the priest Isaiah was called to be a prophet (Isaiah 6), and that he accepted this ministry. We know that he was an adviser to kings–specifically to Uzziah and to Hezekiah. We know that he was a very brave person, as he called Israel out for her sin. Considering that he lived 2700+years ago, we know quite a bit about Isaiah. How many people who lived 2700 years ago do we know this much about?
As for the others on the list–Obadiah, Joel, Nahum (and most also list Malachi in this oft-repeated criticism), it is true in these four cases that we know quite little about these prophets. Unlike Isaiah, who we know quite a bit about, we know almost nothing about these four. My response to this is this: Why do we need to know a lot of personal information about a prophet? What we need to know about a prophet is that he was in fact a prophet and that he spoke for God. In the case of Joel a number of his prophecies came true. For example, Joel 2:28-32 was fulfilled on the Day of Pentecost, as mentioned by Peter. Also, the prophecies in Malachi 3:2 and Malachi 4:5-6 were fulfilled in the person of John the Baptist. That these prophets were inspired and spoke for God is confirmed by the fulfillment of their prophecies. Again, what is the “rule” that says we have to know a lot of personal details about a prophet in order to believe what they spoke was from God? Apparently, the Jews who knew these prophets considered them to be true prophets, and they would be the ones to know.
Add to this is the hypocrisy of Muslims who make this charge. I call this hypocritical because there are a number of prophets in the Koran about whom we know essentially nothing. This includes the supposed prophets Hud and Saleh. We do not know when they lived, where they lived the name of their parents, wives or offspring. Does this mean that they are false prophets? Do Muslims renounce their own prophets about whom they know virtually nothing?
This is what is known as a red herring argument. It is an issue which is raised which has little or nothing to do with the question. The question is whether Isaiah or Obadiah were in fact prophets who spoke for God. This question is not affected, either pro or con, by how much we know about their personal lives. This is a non-issue, raised by Muslims because the do not have true prophets who made real, verifiable prophecies of the future which in fact were fulfilled in history. They have NOTHING like Isaiah 53 or Isaiah 7:14 or Isaiah 9:1-6 or Zechariah 9:9 or Psalm 22:15-17. These are REAL prophecies, the equivalent simply does not exist anywhere in the Koran. This issue is a diversionary effort to distract from the fact that the Koran does not have proof of inspiration like the Old Testament does.