50 is an important number in Scripture.
There’s the Year of Jubilee, when slaves were freed and debts were cancelled.
Leviticus 25:10 (ESV)
You shall consecrate the fiftieth year, and proclaim liberty throughout the land.
And there’s Pentecost.
In Exodus, the Feast of Weeks celebrated the wheat harvest, seven weeks after the First Fruits barley harvest. In the New Testament, Jesus rose from the dead on the Day of First Fruits. and the Spirit came seven weeks later. Pentecost (in Greek, pentékosté) means 50th day — seven weeks from Easter to Pentecost Sunday.