Be faithful in small things because it is in them that your strength lies. Nothing is small for our good God, for he is great and we are small. That is why he lowers himself and cares to do small things, in order to offer us an opportunity to show him our love. Since he does them, they are great things, they are infinite. Nothing he does can be small. Again: practice fidelity even in the least things, not for their own sake, but for the sake of what is great – that is, the will of God.
Source: A Life for God