What is it?

Manna? What is it? That's what the Israelites said when they saw the white stuff on the ground in the morning. Here in the middle of the desert God provided this sweet bread everyday. Infact, for 40 years he miraculously provided this for them. They had to trust God to provide for them because they were only supposed to gather what they needed for the day and on the sixth day to gather twice as much. If they gathered more than what they needed thinking that they needed to store up for the next day...the manna would be filled with maggots and would stink. BUT, on the sixth day when they gathered enough for two days the manna was fine. Some didn't gather extra on the sixth day and when they got up to gather manna on the seventh day...there was none to gather. God's ways are such a mystery. And yet, there are so many lessons from this. Jesus calls himself the true bread from heaven. Although this manna allowed them to physically live when they shouldn't have, Jesus makes us come alive spiritually - when we were once dead. Jesus is the bread of life. I must partake of this bread daily and allow my life to be nourished and sustained by him. I must also recognize my need for rest and truly take a Sabbath every week.
The Lord commanded Moses to take some of the manna and put it in a jar. This must have miraculously remained maggot-free and stink-free. Also it says that the mann was put "in front of the Testimony." What is that? The tabernacle wasn't built yet and the law had not been given.
What is the "commands and instructions" that is mentioned in 16:28 and the "decrees and laws" mentioned in 18:20? I think these were what God was giving to the people through Moses. It just seems weird that these terms are used before the Sinai Law was given. Also the first mention of a Sabbath (since Gen 2), before the law is given.
Another interesting thing from this morning's reading is when Jethro comes to visit Moses. Jethro gives Moses good advice in deligating responsibility so that Moses would not get burned out. And there is a beautiful picture in 18:12. "Then Jethro, Moses' father-in-law, brought a burnt offering and other sacrifices to God, and Aaron came with all the elders of Israel to eat bread with Moses' father-in-law in the presence of God."
This explanation is interesting to me. Something about Jethro (priest of Midian) and coming together with Aaron and the elders that speaks of Christ. Jesus shows that He is a God who fellowships with His people. He eats with us. He loves parties and is always throwing a banquet. A question just came to me. What is the BREAD that they ate? They were in the desert and God was sending manna to them every day. Was it the manna that they ate? And its significant that they ate this "in the presence of God." Totally fascinating to me.