Shortly after Solomon became king the Eternal appeared to him in a dream and offered to give him ANYTHING (1Kings 3:5), which included being rich as were most kings on the earth. He requested, however, "an understanding heart" (verse 9) so that he could fulfill his responsibilities as king over all of Israel. God's response to his selfless request was amazing and unique.
12 I will do what you (Solomon) have asked. I will give you more wisdom and understanding than anyone has ever had before or will ever have again. 13 I will also give you what you have not asked for: all your life you will have wealth (be rich!) and honor, more than that of any other king. (1Kings 3:10 - 13)
God not only promised to make Solomon the wisest man ever but also to make him uniquely RICH.
There are four primary ways King Solomon, in a fairly short period of time, became the wealthiest king alive. He was made rich through commerce and trading, gifts he received, tribute money paid to him and heavy taxation.
Commerce and Trading
"King Solomon also built a fleet of ships at Ezion Geber . . . Then Hiram (King of Tyre) sent his servants with the fleet, seamen who knew the sea, to work with the servants of Solomon. And they went to Ophir, and acquired FOUR HUNDRED AND TWENTY TALENTS OF GOLD from there . . ." (1Kings 9:26-28)
His partnership with Hiram also brought him, every three years, things like ivory, monkeys, apes, etc. (1Kings 10:22-23). The Jewish historian Josephus also wrote about his rich trading for gold and silver.
" . . . for the King had many ships which lay upon the sea of Tarsus, these he commanded to carry out all sorts of merchandise unto the remotest nations, by the sale of which silver and gold were brought to the king, and a great quantity of ivory, and Ethiopians, and apes; and they finished their voyage, going and returning, in three years' time" (Antiquities of the Jews, Book 8, Chapter 7).
The Queen of Sheba came special to Jerusalem to hear Solomon's wisdom. She was so impressed that she gave him camels, jewels, a large quantity of gold and other gifts.
9 She (Queen of Sheba) presented to King Solomon the gifts she had brought: almost five tons (other translations say 'one hundred and twenty talents') of gold . . . (2Chronicles 9:1, 9)
The Bible says that everyone who came to inquire of the king's wisdom brought him a gift - either animals, spices, precious metals and so on (1Kings 10:25). Josephus also wrote about how rich Solomon was through the gold and other goods he received.
"Now the weight of gold that was brought him was six hundred and sixty-six talents, not including in that sum what was brought by the merchants, nor what the toparchs and kings of Arabia gave him in presents."
"Accordingly there went a great fame all around the neighboring countries, which proclaimed the virtue and wisdom of Solomon, insomuch that all the kings everywhere were desirous to see him, as not giving credit to what was reported, on account of its being almost incredible. They also demonstrated the regard they had for him by the presents they made him; for they sent him VESSELS OF GOLD, and silver, and purple garments, and many sorts of spices, and horses, and chariots, and as many mules for his carriages as they could find proper to please the king's eyes, by their strength and beauty." (Antiquities of the Jews, Book 8, Chapter 7)
Tribute is money or goods paid by kingdoms or countries in acknowledgment of another country's superiority.
"They brought tribute and served Solomon all the days of his life. . . ." (1Kings 4:24)
Rehoboam, after he assumed the throne of his father, travelled to the city of Shechem where many of the northern tribes of Israel gathered to make him king. The people told the king, in no uncertain terms, what his father required of them. Their response makes it clear that Rehoboam's father was rich, in part, off the backs of the people he ruled.
'Your father Solomon treated us harshly and placed heavy burdens (he taxed them heavily) on us. ' (1Kings 12:4)
How much GOLD did he own and what was it worth?
While the Bible does not give us a value or weight of all the silver, bronze, precious gems, garments, spices, etc. that came to Solomon, it does give us a rough idea how much gold he brought in and how rich he was.
14 Every year King Solomon received over twenty-five tons (other translations say 'six hundred and sixty-six talents') of gold, 15 in addition to the taxes paid by merchants . . . (1Kings 10)
Used anciently, Talents were a measure of weight and money. A talent weighs roughly 75 U.S. pounds (34.3 kilograms), which is equal to 1,094 troy ounces. At $1,500 per troy ounce, a talent of gold in today's value is worth $1,641,000. At $1,600 per troy ounce, a talent is worth $1,750,400. Solomon received 666 talents of the metal EACH YEAR. This means the value of what he got each year was between $1,092,906,000 and $1,165,766,400 U.S. dollars!
The king became so immensely rich that ALL his cups were made of gold (not one was made of silver - 1Kings 10:21). His wealth was so immense that gold and silver were as common in Jerusalem as STONES (2Chronicles 1:15, see also 1Kings 10:27)!
What exactly was Solomon's net worth? Exactly how rich was he? There has never been a human in history who had SO MUCH gold and silver "at his fingertips" such that it was as common as pebbles! Since we know he ruled Israel for forty years, and that he brought in roughly 1.1 BILLION dollars of gold EACH YEAR, we can safely assume his assets were in the billions of dollars.
Solomon, however, possessed even MORE riches than what was mentioned above. He also inherited wealth from his father David, regularly received gold and silver from the kings of Arabia, governors and merchants, and heavily taxed his own people. Additionally, as if that was not enough, he received tribute money from countries and kingdoms, plus gold, silver, ivory, animals, slaves and so on every three years due to his business partnership with the King of Tyre AND he garnered gifts of gold, spices, precious stones, garments, armor, and so on EACH YEAR from a variety of others!
It is safe to say that the king was certainly RICH, and likely one of the top ten wealthiest humans EVER given the amount and variety of goods that came to him on a regular basis!
What did wisdom teach him?
God made Solomon the wisest human who would ever live. With such a gift, the king felt it was necessary to write down what he understood and pass it on to others for their benefit. The result of his efforts was the Book of Proverbs, where he wrote concerning being rich and its true place in life.
"Happy is the man who finds wisdom, and the man who gains understanding; For her proceeds are better than the profits of silver, and her gain than FINE GOLD" (Proverbs 3:13 - 14)