“He hath shewed strength with his arm; he hath scattered the proud in the imagination of their hearts (Luke 1:51).”
This verse is found in the middle of the song of Mary from Luke 1:46-56. Throughout the Old Testament, we find the strength of God being described by an arm or hand. In Psalm 89:13, Ethan the Ezrahite describes the LORD God of hosts as having a mighty arm and a strong hand. Elsewhere in the prophets, Isa. 52:10 mentions that the LORD had made bare his holy arm in the eyes of all the nations. It is interesting to me that this same chapter of Isaiah has another reference to the coming Messiah, Jesus Christ. You can see that reference in Isa. 52:7.
Perhaps one Old Testament event that Mary had in mind was the deliverance of the people of Israel against the Pharaoh of Egypt. This occurred when he and his army of chariot soldiers chased the Israelites through the Red Sea. It is said that as the Egyptians were following the Israelites the wheels of their chariots fell off, for the LORD was fighting against them (Ex. 14:25). After the victory against the Egyptians, we find what is referred to as the song of Moses in Exodus 15.
At Ex. 15:6 Moses declares that the right hand of the LORD is become glorious in power and dashed in pieces the enemy. Then after further mentioning that God is glorious in holiness, he says that the LORD had stretched out his right hand, and the earth swallowed them up (Ex. 15:11-12).
Mary was indeed right to praise God for the strength his arm. The LORD’s hand is not shortened, that it cannot save (Isa. 59:1).