The name Pharaoh gave Joseph was Zaphnathpaaneah, a fifteen letter name.
The book of 1Peter contains material from fifteen Old Testament books.
Two of the top ten most frequently mentioned women in the word of God, Abigail and Miriam, are mentioned 15 times.
The longest words in the KJV Scriptures that are not names number fifteen letters in length. They include words such as administrations (1Corinthians 12:5), bloodguiltiness (Psalm 51:14), fellowprisoners (Romans 16:7), notwithstanding (Exodus 16:20), righteousnesses (Isaiah 64:6), stumblingblocks (Jeremiah 6:21) and unrighteousness (Leviticus 19:15).
It was in the 15th year of the reign of Tiberius Caesar's reign that John the Baptist's ministry began (Luke 3:1 - 3).
There are at least fifteen promises to Christians listed in the book of Matthew.
The Kingdom of heaven (Matthew 5:3)
We will be filled with righteousness (5:6)
We shall see God (5:8)
Will be called the children of God (5:9)
Our names confessed before God the Father (10:32)
We will be given rest (11:29)
God will consider us part of his family (12:50)
We shall become fully converted (18:3)
We shall be great in God's Kingdom (18:4)
We will be able to receive Christ (18:5)
Our requests made with others will be granted (18:19)
Christ will be with us (18:20)
We will be saved (24:13)
We serve Jesus by serving others (25:40)
Jesus will always be with us (28:19)
Additional information on the Biblical Meaning of Number 15
For Christians, the first day of the Feast of Unleavened Bread (Nisan 15) pictures rest from their sins, having had them removed by Christ’s shed blood on Passover. The 15th day of the 7th month begins the Feast of Tabernacles. For the children of Israel, it pictured rest from the long harvest season. They were to dwell in booths in remembrance of their trek in the wilderness.
Prophetically, the 15th day of the 7th month pictures the coming Millennium when the world will have rest from sin because of the binding of Satan on the Day of Atonement. Under Christ’s reign, salvation will then be offered to all the world, becoming the great spiritual harvest of God for 1,000 years.