4 - some more examples from the New Testament

1. Four men who had made a vow are mentioned in Acts 21 (Acts 21:23) 
2. Four anchors were dropped from the ship that took Paul to Rome (Acts 27:29) 
3. Four living creatures are mentione in Revelation 4-6, etc
4. Four horses with riders appear when the first four seals of the seven are opened (Revelation 6)
5. Four angels are seen standing at the four corners of the earth, holding back the four winds of the earth to prevent any wind from blowing on the land or on the sea or on any tree in Revelation 7
6. Four markers are used to describe the multitiude who are saved, they are from every nation, tribe, people and language (Revelation 7:9) 
7. Four horns on the golden altar are referenced in Revelation  9:13
8. Four angels previously bound are released to kill a third of mankind in Revelation 9
9. The four corners of the earth are where people will be gathered from for the great battle (Revelation 20:8)
10. Four sides are found to the New Jerusalem (Revelation 21:6)