What does the Bible say about how God's kingdom is gathered?

In Matthew 13:47-50, Jesus describes the kingdom of heaven as a net cast into the sea which gathers fish of every kind. This illustrates how the gospel, when preached, calls out God's elect from different backgrounds and conditions. The imagery of the net emphasizes that while the gospel is offered to all, there will be a distinguishing at the end of the age when God’s angels separate the righteous from the wicked. This gathering reflects God’s sovereign choice in bringing His people into His kingdom, showcasing His grace and mercy towards His elect.