And Mary said: “My soul magnifies the Lord, and my spirit has rejoiced in God my Savior. Luke 1:46-47, 49
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My personal interpretation goes this way:
Magnify means to make bigger. A second meaning is to glorify. Mary doesn’t just say “I magnify the Lord.” She says her soul and spirit do!
Her soul is so overwhelmed by God’s saving message to her and being chosen to bear the Christ, it cannot be contained! It is to much for human flesh, so her soul, her spirit burst forth in the effort to enlarge God in her existence, to glorify Him.
Jeffrey H. King's Blog 
Agreed, Jeff. Mary’s whole being was consumed with praise to God for His gift to her. This reminds me of the verse from the Old Testament: “Love the Lord your God with your whole heart, soul, mind, and spirit.” Have a blessed Christmas, brother!
Merry Christmas!!