Devotion to the holy Name of Jesus was particularly encouraged by Sts. Bernard of Clairvaux, Bernadine of Siena and John Capistran, but the principle goes back much earlier. Paul in Philippians 2.9-11 wrote,
Therefore God also highly exalted him
and gave him the name
that is above every name,
so that at the name of Jesus
every knee should bend,
in heaven and on earth and under the earth,
and every tongue should confess
that Jesus Christ is Lord,
to the glory of God the Father.
and Fr. Steven Peter Tsichlis writes:
The Jesus Prayer is rooted in the Name of the Lord. In the Scriptures, the power and glory of God are present in his Name. In the Old Testament to deliberately and attentively invoke God's Name was to place oneself in his Presence. Jesus, whose name in Hebrew means God saves, is the living Word addressed to humanity. Jesus is the final Name of God. Jesus is "the Name which is above all other names" and it is written that "all beings should bend the knee at the Name of Jesus" (Phil. 2:9-10). In this Name devils are cast out (Luke 10:17), prayers are answered (John 14:13 14) and the lame are healed (Acts 3:6-7). The Name of Jesus is unbridled spiritual power.
The Jesus Prayer of course dates back at least to the 4th or 5th century AD, where it arose in the Egyptian desert among the people we now know as the Desert Fathers and Mothers.
Today we celebrate the naming of Jesus with the Name which was given to his mother Mary by the angel Gabriel. Truly this is the Name above all names - let us worship him in whose Name we are saved!