The mind wanders and the will falters again and again… But it is foolish to allow failures in concentration to plunge us into profitless self-condemnation. A mother does not condemn her child who is struggling with many a failure to learn how to walk, but rather she is pleased by each successful effort… I like to believe that God is similarly pleased with our efforts and understanding of our many failures. What matters is whether or not the will, like a compass needle when deflected, is so pivoted that it can swing back to the true direction.

St Francis de Sales is reassuring:

When your heart is wandering and distracted, bring it back quickly to its point, restore it tenderly to its Master’s side, and if you did nothing else the whole of your hour but bring back your heart patiently and put it near our Lord again, and every time you put it back it turned away again, your hour would be well-employed.

Thomas F Green, 1952