What is the remedy for prayer when one discovers that their ablution and prayer were incomplete, and they become plagued by obsessive doubts regarding washing the hands, or placing one hand before the other during prostration, or a slight deviation from the Qiblah? And what should one do upon committing a continuous sin or when obsessive doubts about these matters arise?

The treatment for obsessive thoughts (waswas) is to ignore them and pay them no mind. If the ablution (wudu) is deemed invalid, there is a difference of opinion regarding the necessity of re-performing the prayers. There is no harm in adopting the view that the one afflicted with waswas is not required to re-perform them. Rubbing the limbs (dalk) during ablution is not obligatory, and placing one hand before the other in prostration (sujud) or a slight deviation from the Qibla does not invalidate the prayer. The questioner is advised to learn what is obligatory in ablution and prayer, to cast away obsessive thoughts, and to offer sincere repentance for sins, for "the one who repents from sin is like one who has no sin."