The Meaning of Numbers: The Number 10,000
The number 10,000 derives part of its meaning from the fact that it is sometimes used to denote a group that is innumerable or countless (see Paul and Revelation's use below). It also has a relationship with several Judges of Israel.
Haman, Prime Minister of Persia, was willing to pay the empire's king 10,000 talents of silver (worth around $180 million today) to defray the cost of murdering all the Jews in the kingdom (Esther 3:9)!
Deborah, a prophetess who was Israel's Judge, summons a man named Barak. Inspired by God, she charges him with gathering 10,000 men to fight King Jabin's army in order to free Israel of his twenty-year oppression (Judges 4:1 - 7, 14). Barak agrees to lead the army into battle only if Deborah comes with him (verse 8). After Israel defeats their oppressor the people enjoy forty years of peace (5:31).
Appearances of the number ten thousand
God made a unique promise to the children of Israel. If they obeyed him, keeping his commandments and statutes, he promised to do something miraculous concerning their enemies.
And five of you shall chase a hundred, and a hundred of you shall put ten thousand (10,000) to flight. And your enemies shall fall by the sword in front of you (Leviticus 26:7, HBFV).
Moses, in another place, uses a variation of this promise in his final admonishment of the Israelites before his death.
How shall one chase a thousand, and two put ten thousand to flight, unless their Rock had sold them and the Lord had shut them up? For their rock is not as our Rock, even our enemies themselves being judges (Deuteronomy 32:30).
Gideon is called by God to free his people from Midianite domination. He sends messengers to four Israelite tribes asking men to volunteer to fight (Judges 6:1 - 35). About 32,000 men show up. Those who are afraid or fearful are told to go back home, leaving an army of 10,000 (Judges 7:2 - 3). God ultimately whittles down the army to only 300 before it can win a mighty victory (verses 4 - 7).
God called Ehud, a rare left-handed warrior, to save his people from the oppression of the Moabites (Judges 3:12 - 15). After killing Eglon, Moab's king, Ehud rallies the Israelites to fight against their enemies. He leads God's people to slay 10,000 men "all lusty" (Judges 3:29, KJV) and men of valor.
Apostle Paul and the number 10,000
Paul loved the church at Corinth in spite of their many difficulties and the tremendous effort he expended on their behalf. He expressed his special spiritual relationship with them using 10,000.
For you might have ten thousand tutors in Christ, but you do not have many fathers; for in Christ Jesus I did beget you through the gospel (1Corinthians 4:15).
Apostle Paul, several chapters later, again uses 10,000 to illustrate a point. He utilizes it to show the overwhelming importance of speaking words that others can understand versus the overrated gift of speaking in tongues (other languages).
But in the church, I desire to speak five words with my understanding rather than ten thousand (10,000) words in an unknown language, so that I may also instruct others (1Corinthians 14:19).
More info on Biblical Meaning of 10,000
In the Bible, 10,000 is used in its last book to describe the vast quantity of righteous spirit beings that surround the Eternal's throne. If taken literally, the verse in question is likely delineating the largest number recorded in God's word!
And I beheld, and I heard the voice of many angels round about the throne and the beasts and the elders: and the number of them was ten thousand times ten thousand, and thousands of thousands (Revelation 5:11, KJV).