Question: "What was inside the ark of the covenant?"
Answer: Interestingly, the most complete inventory of the contents of the ark of the covenant is found in the New Testament: Hebrews 9:4 says that the Most Holy Place had “the gold-covered ark of the covenant. This ark contained the gold jar of manna, Aaron’s staff that had budded, and the stone tablets of the covenant.” The stone tablets were those on which God had written the Ten Commandments.
At various times in Israel’s history, it seems that various items were in the ark of the covenant. When God first gave Moses the instructions on building the ark, He said, “Put in the ark the tablets of the covenant law, which I will give you” (Exodus 25:16).
Sometime during the wilderness wanderings, God commanded that a container of manna be added to the ark’s cargo: “Moses said to Aaron, ‘Take a jar and put an omer of manna in it. Then place it before the Lord to be kept for the generations to come.’ As the Lord commanded Moses, Aaron put the manna with the tablets of the covenant law, so that it might be preserved” (Exodus 16:33–34).
After the rebellion of Korah, God commanded the leader of each tribe of Israel to bring a staff to the tabernacle. The name of each leader was inscribed in his staff; the tribe of Levi bore Aaron’s name. God instructed that the staffs be placed in the tabernacle overnight. The next morning, Aaron’s rod “had not only sprouted but had budded, blossomed and produced almonds” (Numbers 17:8) as a sign of God’s blessing on the Levitical priesthood. God then said, “Put back Aaron’s staff in front of the ark of the covenant law, to be kept as a sign to the rebellious” (verse 10).
So, by the time Israel reached the Promised Land, the ark was associated with the items mentioned in Hebrews 9:4: the stone tablets, the jar of manna, and the staff of Aaron.
When King Solomon’s temple was finished, the king had the ark of the covenant, along with all the other furnishings of the tabernacle, brought to the new temple’s dedication. At that time, the biblical historian notes that “there was nothing in the ark except the two stone tablets that Moses had placed in it at Horeb” (1 Kings 8:9; cf. 2 Chronicles 5:10).
There are two possible ways to reconcile 1 Kings 8:9 with Hebrews 9:4. One is that the ark in Moses’ time contained all three items mentioned in Hebrews but, by Solomon’s time hundreds of years later, only the stone tablets remained. The other items could have been removed in Eli’s time by the men of Beth Shemesh when “they looked into the ark of the Lord” (1 Samuel 6:19). Before that, the ark was in the possession of the Philistines for a time, and they could have removed some of the ark’s contents. It could also be that Solomon himself had the manna and the staff removed from the ark and set nearby in the same room at the time of the temple’s dedication.
Another possibility is that the jar of manna and Aaron’s staff were not usually inside the ark of the covenant, but rather <beside it. God’s command in Exodus 16:33 was for Moses to place the manna “before the LORD” (ESV) or “in a sacred place before the LORD” (NLT). Similarly, the staff was to be placed “before the testimony” (Numbers 17:10, ESV) or “permanently before the Ark of the Covenant” (NLT). So, the manna and the staff were kept in the same place as the tablets of stone, but it’s possible they were not, strictly speaking, inside the ark.
It’s also quite possible that the jar of manna and Aaron’s staff were carried inside the ark every time the ark was moved. When the ark was at rest in the Most Holy Place, the manna and the staff were placed beside or in front of the ark. But, while the ark was in transit, the most practical place to carry the manna and the rod was inside the ark.