Before the first coming of Christ, the Jews were so concerned about taking God's name in vain, that they decided never to say His name at all. Whenever they came upon the name of God is Scripture they just said "Lord" instead. Although that is a good motive, it is not the greatest manner of implementation.
By contrast, when God wanted to reveal to us more about His "name" (which in Jewish thinking means His character, personality, and traits), He sent His Son to become incarnate. God gave us more opportunity to speak His name rather than less. The Second Person of the Trinity took on human flesh in order to reveal the First Person of the Trinity. Then, the Third Person of the Trinity, the Holy Ghost, came to reside within us to encourage us to follow the Second Person to the First Person.
In other words: the ancient Jews avoided saying God's name in order to make His holiness known. God made His holiness known by naming His spoken Word . . . and He named Him Jesus.