What is the ruling on repeating a prayer when one experiences excessive waswas (whispers/intrusive thoughts) during it?

A servant must attain khushu' (devotional humility) in prayer and avoid being carried away by whispers (waswas) and thoughts. This is because thinking about things that contradict thew prayer diminishes or eliminates khushu'. Nevertheless, thinking about matters outside of prayer does not invalidate it, even if it is extensive or concerns something forbidden. The remedy for waswas is to completely disregard them.