Here [Robert Bellarmine] inspires readers with a reflection on verse one of Psalm 91, "He who dwells in the shelter of the Most High":
Notice that what is said is not "he who trusts" ... but "he who dwells." This is to convince us that we are not to fly to the divine protection as men do to a tree or a doorway when it rains, but rather as little boys who run to their father's arms when anything frightens them. They know that they have mother and father there who would gladly give their hearts' blood to protect them.
But people who seek refuge from rain under a tree, have a good look round first. It is only when no better shelter is available that they run willy-nilly to the tree. Why is it that some men implore divine assistance without receiving it, and seem to put their trust in God without being protected by him? The reason is that they do not really dwell in the aid of the Most High, or take shelter under the providence of God as in their Father's house. They rather make sporadic dashes to it in time of trouble, as they do to a tree when there is a sudden shower. It is therefore very necessary for us to get into the way of always and instinctively turning to God.
Saint Robert Bellarminevia Voices of the Saints by Bert Ghezzi