Isidore said:

Prayer is a work of the heart, not of the lips. For God does not pay attention to the words of the one who is praying to him, but rather to his or her heart. It is better to pray in the silence of the heart than to pray only with words, without the mind paying attention.

It is useless to pray when trust and hope are missing.

Our spirit contemplates God perfectly only if it is not obstructed by earthly anxieties.

– Defensor Grammaticus

The Book of Sparkling Sayings