A prayer before writing from Thomas Aquinas (1225-1274):

O Creator of the universe, who has set the stars in the heavens and causes the sun to rise and set, shed the light of your wisdom into the darkness of my mind. Fill my thoughts with the loving knowledge of you, that I may bring your light to others. Just as you can make even babies speak your truth, instruct my tongue and guide my pen to convey the wonderful glory of the Gospel. Make my intellect sharp, my memory clear, and my words eloquent, so that I may faithfully interpret the mysteries which you have revealed.