We know that God supernaturally delivered Israel. At the burning bush Moses was being prepared to trust God to bring about that glorious work. He would learn something about God's nature that would later help him trust the Lord to bring it all to pass. What was that aspect of God's nature? His holiness!
The same is true for every Christian today. We may try to accomplish in the flesh what we think God wants. But the Lord says to us as he did to Moses, "There is only one ground upon which you can approach me, and that is holy ground. You can't put any confidence in your flesh, because no flesh will stand in my presence. My purposes are never accomplished by what you can summon up in yourself."
So, why did God tell Moses to take off his shoes? (See Exodus 3:5.) The Lord was using an everyday, ordinary object to teach a spiritual truth, just as Jesus would do using coins, pearls, camels and mustard seeds. God was saying, "Moses, you have to wear protective garb to keep your feet from injury. But no amount of fleshly protection can sustain you where I am sending you. You'll need a miracle of deliverance.
"I am sending you into Egypt, to face a hardened dictator. You'll be in a situation from which only I can deliver you. So, set aside all reliance on your flesh, even your meekness and humility. Otherwise, you won't be able to do what I'm calling you to do. All your abilities will be worthless unless I sanctify them. Put your total trust in my name and power."
No one can achieve holiness in God's sight by his own strength or willpower. We can't even serve the Lord properly without taking the approach outlined to Moses. We must come to God saying, "Lord, I have nothing to give you. You have to do it all."