While we may not always realize it, the name of Jesus has a great deal of spiritual power that can positively influence our soul.
This is one of the reasons why the Church instituted a feast dedicated to the Holy Name of Jesus.
St. Bernard is one of the many saints who reflected on the power hidden in the name of Jesus and how it can affect us.
Light
Dom Prosper Gueranger quotes St. Bernard's sermon in his Liturgical Year, first focusing on the connection the name of Jesus has to light:
Tell me, whence came there into the whole world so bright and sudden a light if not from the preaching of the Name of Jesus? Was it not by the light of this Name that God called us unto his admirable Light? Wherewith being enlightened and in this light seeing the Light we take these words of Paul as truly addressed to ourselves, "Heretofore you were darkness, but now light in the Lord."
Food
In addition to being light, St. Bernard also saw the name of Jesus as being, "food" to the soul:
Nor is the Name of Jesus Light only it is also Food. Art thou not strengthened as often as thou thinkest of this Name? What is there that so feeds the mind of him that meditates upon this Name? What is there that so restores the wearied faculties, strengthens virtue, gives vigour to good, and holy habits, and fosters chastity? Every food of the soul is dry that is not steeped in this unction; it is insipid if it be not seasoned with this salt. If thou write, I relish not thy writing unless I read there the Name of Jesus. If thou teach me or converse with me, I relish not thy words unless I hear thee say the Name of Jesus. Jesus is honey to the mouth and music to the ear and gladness to the heart.
Medicine
St. Bernard also saw the name of Jesus as a type of "medicine" for us:
It is also Medicine. Is any one among you sad? Let but Jesus come into his heart and the mouth echo him, saying Jesus, and lo the light of that Name disperses every cloud and brings sunshine back again. Have any of you committed sin and is despair driving you into the snare of death? Invoke the Name of life and life will come back to the soul. Was there ever a man that hearing this saving Name could keep up that common fault of hardness of heart or drowsiness of sluggishness or rancor of soul or languor of sloth? If any one perchance felt that the fountain of his tears was dry, did it not gush forth more plentifully than ever and flow more sweetly than ever as soon as he invoked the Name of Jesus?
St. Bernard reminds us that the name of Jesus is spiritually powerful and the simple recitation of his name can bring peace to our wearied soul.