Is one sinful for praying without humility, such that it resembles the prayer of the hypocrites, and is one sinful for being carried away by worldly thoughts during prayer?

Humility (khushu') in prayer is recommended by most scholars. One who lacks it does not sin, nor is he required to repeat the prayer, and his prayer is valid as long as he fulfills its conditions and pillars. Humility is the essence and spirit of prayer. Allah has praised the believers who are humble in their prayers. One who abandons humility misses out on a great bounty and a tremendous reward. Indulging in worldly thoughts during prayer is not considered a forbidden act, but it causes one to miss out on the reward of presence of heart and complete humility. Hypocrites do not exhibit humility in their prayers, as Allah Almighty says: "And when they stand for prayer, they stand lazily, showing off to the people and not remembering Allah except a little." The aforementioned statement may aim to deter one from abandoning humility, as it is a characteristic of hypocrites.