Sahih al-Bukhari 1116

(who had piles) I asked Allah's Messenger (ﷺ) about the praying of a man while sitting. He said, "If he prays while standing it is better and he who prays while sitting gets half the reward of that who prays standing; and whoever prays while Lying gets half the reward of that who prays while sitting."

"I asked Allah's Messenger (S) about the Salat for a man who is sitting. He said: 'Whoever performs Salat while standing then that is more virtuous. And whoever performs Salat while sitting, then he gets half the rewards of the one standing, and whoever performs Salat while lying down, then he gets half the rewards of the one sitting.'"

‘Imran b. Hussain asked the prophet (ﷺ) about the prayer a man offers in sitting condition. He replied: his prayer in standing condition is better than his prayer in sitting condition, and his prayer in sitting condition is half the prayer he offers in standing condition, and his prayer in lying condition is half the prayer he offers in sitting condition.

"I asked the Prophet (ﷺ) about one who prays sitting down. He said: 'Whoever prays standing up is better, and one who prays sitting down will have half the reward of one who prays standing up. And whoever prays lying down will have half the reward of one who prays sitting down.'"

It was narrated from ‘Imran bin Husain that he asked the Messenger of Allah (ﷺ) about a man who prays sitting down. He said, “Whoever performs prayer standing up, that is better. Whoever performs prayer sitting down will have half the reward of one who prays standing. And whoever performs prayer lying down will have half the reward of one who prays sitting.”