It is narrated from Hazrat Abu Qatadah (may Allah be pleased with him) that the Noble Prophet (peace and blessings be upon him) said: The worst thief among people is the one who steals from his prayer. The people asked, "O Messenger of Allah! How can a person steal from his prayer?" The Noble Prophet (peace and blessings be upon him) replied: By not performing the bowing (ruku) and prostration (sajdah) properly and completely.
Hadith Referenceمسند احمد / مسند الأنصار رضي الله عنهم / 22642
Hadith Gradingحکم دارالسلام:حديث صحيح، وتكلم فيه الإمام على بن المديني