Lots of books were left out of the Bible ....
Well, I am only going to reply to the "Thread Title" or this part or portion of what you had written.
So are there lost books of the Bible or the Holy Scriptures?
Yes, but we do not need them. The Bible (or all the Scripture we have) is all we need for doctrine, instruction, and training in righteousness (2 Timothy 3:16-17). But there are other books mentioned in the Holy Scriptures themselves that we do not get to actually see as a part of the traditional 66 book collection. Here is a list of unseen books (mentioned in the Bible itself) I compiled with a little help from an article I read a long time ago.
The Different Books (or Words) Mentioned in the Bible (That We Never Got To See):
A. Heavenly Books:
#1. The Word of God in Heaven (For the Words of the Lord are Forever Settled in Heaven).
#2. The Lamb's Book of Life.
#3. The Book of Remembrance.
#4. Unnamed Book That Has All Our Members Written Within It.
#5. The Book (Scroll) of the Seven Seals.
#6. Unnamed Books of Judgment.
#7. The Unnamed Little Books That Ezekiel and John Eat.
B. Earthly Books:
I.
Spiritual and or Prophetic:
#1.. Samuel's Book of the Manner of the Kingdom.
#2. The Book of Nathan the Prophet.
#3. The Book of Gad the Seer.
#4. The Acts of Solomon.
#5. Solomon's Many Other Proverbs and Songs.
#6. The Prophecy of Ahijah the Shilonite.
#7. The Story of the Prophet Iddo.
#8. The Visions of Iddo the Seer.
#11. The Book of Shemaiah the Prophet.
#12. The Sayings of the Seers.
#13. Paul's Earlier Epistle to the Corinthians About Fornication (1 Corinthians 5:9).
II.
Historical:
#1. The Book of the Living.
#2. The Book of the Wars of the Lord.
#3. The Book of Jasher.
#4. David's Letter to Joab.
#5. The Book of Jehu.
#6. Jehu's 1st Letter to Samaria.
#7. Jehu's 2nd Letter to Samaria.
#8. Unfinished Record of Princes Not Added to Chronicles.
#9. Writings of David and Solomon on Passover Keepings.
#10. Actions of King Uzziah Not Recorded in the Book of Isaiah.
#11. Mordecai's Purim Announcement Letter to the Jews.
#12. Esther & Mordecai's 2nd Confirmation Letter of Purim.
C. Possible Other Books.
I.
Heavenly Books:
#1. The Book of the Living (Psalms 69:28).
#2. Library (Larger Than Earth) on the Complete Life of Jesus (See John 21:25).
II.
Earthly Books:
#1. The Book of the Kings of Israel.
#2. The Book of the Kings of Judah.
#3. The Book of the Chronicles of the Kings of Israel.
#4. The Book of the Chronicles of the Kings of Judah.
D. God's People Revealing Past New Oral Prophecies:
#1. Writer of Hebrews Reveals a New Oral Prophecy of Jesus (Hebrews 8:13).
#2. Jude Reveals an Unknown New Oral Prophecy of Enoch (Jude 1:14-15).
E. Secular or Wordly Writings Quoted in God's Word:
I.
God's People Verbally Quoting Secular Writings:
#1. Paul Quotes an Inscription on an Athenian Altar.
#2. Paul Quotes Epimenides' de Oraculis.
#3. Paul Quotes Aratus' Phaenomena (A Poem).
#4. Paul Quotes Menander's Poetry.
#5. Paul Quotes Epimenides' Paradox.
II.
Secular Works Transcribed (In Part or Possibly In It's Entirety):
#1. Jezebel's Letters to the Officials of Naboth's City.
#2. Sennacherib's Letter to Hezekiah.
#3. Huram's Letter to Solomon.
#4. Shemaiah's Letter to Zephaniah on the Exile Prophecy.
#5. King Cyrus's Proclamation to All His Kingdom.
#6. Enemies of Judah Led by 3 Men Write a Letter to Artaxerxes.
#7. Artaxerxes Letter in Reply to the 3 Men.
#8. Govenor Tatnai Writes to Darius About the Jews Rebuilding.
#9. Darius' Decree to Help Rebuild the Temple.
#10. Artaxerxe's Approval Letter to Ezra to Rebuild the Wall.
#11. Sanballat Threatens Nehemiah to Stop Building the Wall.
#12. Chief Captain Claudius Lysias' Letter to Governor Felix.
III.
Secular Works Mentioned By Name But Not Shown:
#1. Benhadad's Letter to the King of Israel.
#2. Berodachbaladan's Letters to Hezekiah.
#3. Artaxerxe's Letters to Nehemiah in Rebuilding the Wall.
#4. Tobaiah & the Judean Noble's Letters Sent to Nehemiah.
#5. The Chronicles of the Kings of Media and Persia.
#6. Xerxe's Unintended Decree (By Haman) to Kill the Jews.
#7. Xerxe's Decree for the Jews to Protect Themselves.
#8. High Priest's Letters Enabling Saul to Round-up Christians.
Please take note that these are actual books (scrolls), writings, or letters mentioned in the Bible. I had verses for each one of these books, but the forum I had posted this one on had taken down a lot of their old posts. In any event, I hope you find this resource helpful and may God bless you all.
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