Spread your arms on your thighs and clap both palms between your knees while praying.

This hadith is about proper posture during prayer. It is narrated by 'Abd Allah b. Masud who was a companion of Prophet Muhammad ﷺ and one of the most knowledgeable people in Islam. He said that when praying, one should spread their arms on their thighs and clap both palms between the knees as if he was seeing the variation of the fingers of Prophet Muhammad ﷺ himself. This shows how important it is to maintain proper posture while praying as it reflects our respect for God and His Messenger ﷺ . It also teaches us to be mindful of our actions even when we are alone, as we are always being watched by God Almighty Himself.