What is the way to expel Satan and get rid of his whispers within oneself during prayer or outside of it?

The best way to expel Satan outside of prayer is to seek refuge in Allah from his whispers, as Allah says: (And say, "My Lord, I seek refuge in You from the whispers of the devils, and I seek refuge in You, my Lord, lest they be present with me.") As for within prayer, it is done by repelling him with seeking refuge and spitting to the left three times, as Uthman ibn Abi al-'As did, by the guidance of the Prophet, peace and blessings be upon him. It is also recommended to reflect upon what is being recited and to perfect one's purification, for these are a great means for a servant's humility in his prayer.