Jon is a shortened form of the name Jonathan

Jon is a shortened form of the common given name of Jonathan, derived from "YHWH has given", and an alternate spelling of John, derived from "YHWH is gracious". In the year of 2008, Jon was the 527th most popular name in the United States; its popularity has declined steadily (sometimes increasing, but not substantially) since its peak in 1968 as #65. Pet forms of Jon include: Jonny, Jon Boy, Jonnie. In Luxembourgish,  Lëtzebuergesch Dictionary]

Jón is an Old Norse common name still widely used in Iceland and the Faroes. According to Icelandic custom, people are generally referred to by first and middle names and patronyms are used if disambiguation is required.

The Book of Jonah is one of the Minor Prophets in the Bible. It tells of a Hebrew prophet named Jonah son of Amittai who is sent by God to prophesy the destruction of Nineveh but tries to escape the divine mission. Set in the reign of Jeroboam II (786–746 BC), it was probably written in the post-exilic period, sometime between the late 5th to early 4th century BC. The story has an interesting interpretive history (see below) and has become well-known through popular children's stories. In Judaism it is the Haftarah for the afternoon of Yom Kippur due to its story of God's willingness to forgive those who repent.