The power of prayer is great even in a sinful person, when it is offered whole-heartedly.
Seraphim of SarovMore Seraphim of Sarov quotes
The Lord sometimes allows people who are devoted to Him to fall into such dreadful vices; and this is in order to prevent them from falling into a still greater sin-pride. Your temptation will pass and you will spend the remaining days of your life in humility. Only do not forget your sin.
Seraphim of Sarov