After the Israelites received the Ark of the Lord back from the Philistines, the people of Beth-Shemesh wanted to look inside it. They knew the original Ten Commandments, which with the finger of God, along with a pot of the manna from the wilderness wanderings, and Aaron’s rod that budded were in the Ark. Those things had been in the Ark for hundreds of years, and the Lord had preserved them. Their curiosity made them look inside,
Then He struck the men of Beth Shemesh, because they had looked into the ark of the LORD. He struck fifty thousand and seventy men of the people, and the people lamented because the LORD had struck the people with a great slaughter (1 Samuel 6.19).
Some translations state that this happened to 70 men rather than 50,070 men.
Either way, it appears to be an incidental reference, because it simply lists the number of men who looked into the Ark of the Testimony.
Sevens in the Bible 
I have been interested in knowing what happened to the ark. According to Revelations John saw it in heaven. Any info on this, you can email it please sir. Thanks
What John saw in the Book of Revelation was the actual Ark, because the one on the Earth was a copy of the heavenly one. Note Hebrews 8.5; 9.23–24. The Ark of the Covenant in the temple during the time of Christ would have been taken by the Romans when they destroyed the temple in AD 70, even as the Arch of Titus shows a depiction of the candlestick that they took from the temple. Are you familiar with the Arch of Titus in Rome?
No… but you shall be my teacher on the subject if you don’t mind.
If you go to this site: http://www.bible-history.com/archaeology/rome/arch-titus-menorah-1.html
You will see the Arch of Titus and there is a depiction on the inside of it that shows the Romans carrying away from Jerusalem the Menorah, the source of light in the temple.