Lord, be my vision, supreme in my heart - Jubilate Hymns
Because I am a sucker for stirring hymns I am just going to cite one verse from the above hymn that we sang at All Souls today:
Lord, be my breastplate, my sword for the fight:
Be my strong armour, for you are my might;
You are my shelter and you my high tower -
Raise me to heaven, O power of my power.