Be Though My Vision is considered by many as the oldest known Christian hymn, dating at least from the 8th or the 9th century, if not even the 6th. Here is what David Cole says about it in his book Celtic Lent: 40 Days of Devotions to Easter:
It is thought that the early Irish saint and poet Dallán, also known as Eochaid mac Colla, who died in around 598, may have been the writer of some early form of this hymn, and the words have been chanted by monks from that time onwards. Although we know it best from the version often sung in churches today, versified as a hymn by Eleanor Hull (1860–1935), the original, more literal, translation from which the versified version was taken was written by Mary Byrne (1880–1931).
Watch here one of the best versions I could find on youtube. I hope it will be an encouragement for you at a trying time like this.
Here is the text of the hymn:
Be Thou my Vision, O Lord of my heart;
Naught be all else to me, save that Thou art.
Thou my best Thought, by day or by night,
Waking or sleeping, Thy presence my light.
Be Thou my Wisdom, and Thou my true Word;
I ever with Thee and Thou with me, Lord;
Thou my great Father, I Thy true son;
Thou in me dwelling, and I with Thee one.
Be Thou my battle Shield, Sword for the fight;
Be Thou my Dignity, Thou my Delight;
Thou my souls Shelter, Thou my high Tower:
Raise Thou me heavenward, O Power of my power.
Riches I heed not, nor mans empty praise,
Thou mine Inheritance, now and always:
Thou and Thou only, first in my heart,
High King of Heaven, my Treasure Thou art.
High King of Heaven, my victory won,
May I reach Heavens joys, O bright Heavens Sun!
Heart of my own heart, whatever befall,
Still be my Vision, O Ruler of all.