"His splendor was like the sunrise; rays flashed from his hand, where his power was hidden." NIV translation
It was by God's power that Abraham was led to Canaan. He simply trusted God in faith and followed. Habakkuk remembers this in his prayer and is strengthened by the fact that God will lead His people if they simply do the same.
"Plague went before him; pestilence followed his steps. He stood, and shook the earth; he looked, and made the nations tremble. The ancient mountains crumbled and the age-old hills collapsed. His ways are eternal. I saw the tents of Cushan in distress, the dwellings of Midian in anguish." NIV translation
Habakkuk continues to remember the fact that God humbled the mighty Egyptians through Moses and Aaron. This passage remembers the ten afflictions of the land of Egypt that convinced them to set God's people free. As he (and we) remember how God has delivered His people, we are assured that the everlasting unchanging God will continue to do the same thing with us and our struggles.
The KJV points to the freedom that was to come for those who believe in Jesus as it speaks of the curtains that separated God from His people. God caused the curtains to tremble at that time but the curtain was torn in two when Jesus was on the cross (see Luke 23:45).
Isn't it cool to see how God is in control of this prayer and uses it to point to the grace that was to come? He will do the same thing with us in guiding our prayers by the power of the Holy Spirit.
"Were you angry with the rivers, O Lord? Was your wrath against the streams? Did you rage against the sea when you rode with your horses and your victorious chariots? You uncovered your bow, you called for many arrows. Selah You split the earth with rivers; the mountains saw you and writhed. Torrents of water swept by; the deep roared and lifted its waves on high." NIV translation
The prophet remembers how God delivered His people from their slavery in Egypt. Even the waters obeyed God as that was an instrument that He used to save His people from the Egyptian pursuers.