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.