It wasnarrated from 'Abdullah bin 'Amr that the Prophet (ﷺ) passedbyhim when he was praying sitting down. He said:
"The prayer of onewho sits down is equivalent to half of the prayer of one who stands." (JA)
English reference (JA): Vol. 1, Book 5, Hadith 1229 (JA)
Arabic reference (JA): Book 5, Hadith 1287 (JA)