Your imagination will wander far and wide, and be affected by the senses and circumstances in which you are placed: but never mind; the imagination is, as St Teresa said, the fool of the house, always making a disturbance, misleading the mind and forcing it to heed the images drawn by itself. You cannot help this, but involuntary distractions will not hurt you.
If you are resolved to resist distraction, you will do so successfully; and whenever you discover it, you will recall your mind to God, calmly and without struggling, not delaying to raise your eyes to him. This faithfulness, in returning to his Presence, will win for you a more abiding sense of it, and thus that Presence will become familiar to you. After a time the practice of speedily returning, the moment you are conscious of distraction, will win for you an habitual easy recollection. But do not suppose you can obtain such by your own efforts; for then you would be perpetually constrained, uneasy, and scrupulous, when you should be free and calm. You would be always fearing that you were losing God's Presence, and striving to retain it, and thus become lost amidst the phantoms of your imagination; and that Presence, the healing light from which should illumine all around, would only serve to render you confused, and almost incapable of your external duties.
Many persons distract themselves, first by their fear of distraction, and then by their regret for such distraction. What would you think of the traveller who, instead of advancing on his way, was always considering the accidents which he might meet with and, after any accident, returned to contemplate the scene thereof? Would you not urge him rather to go forward? Even so I say to you, God on without looking back, so that, pleasing God, you may abound more and more. The abundance of his love will do more to correct you than all your anxious self-contemplation.