It is narrated by Abu Qatadah [ra] that the Prophet (saw) said, “The worst kind of thief is one who steals from his prayer.” The companions said, “O Prophet of Allah how can someone steal from their prayers?” He (saw) said, “He does not fulfill the ruku of the prayer nor its sujood.” [Ahmad]
Abdullah ibn Mughafal reported: The Messenger of Allah, peace and blessings be upon him, said, “Verily, the worst thieves among people are those who steal from their prayers.” It was said, “O Messenger of Allah, how do they steal from their prayers?” The Prophet said, “They do not complete its bowing or its prostration. The most miserly of people are those who are miserly with the greeting of peace.”
Source: al-Muʻjam al-Awsaṭ 3503
Grade: Sahih (authentic) according to Al-Albani
عَنْ عَبْدِ اللَّهِ بْنِ مُغَفَّلٍ قَالَ قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ إِنَّ أَسْرَقَ النَّاسِ مَنْ سَرَقَ صَلاتَهُ قِيلَ يَا رَسُولَ اللَّهِ ، وَكَيْفَ يَسْرِقُ صَلاتَهُ قَالَ لا يُتِمُّ رُكُوعَهَا وَلا سُجُودَهَا وَأَبْخَلُ النَّاسِ مَنْ بَخِلَ بِالسَّلامِ
336 المعجم الصغير للطبراني باب الجيم من اسمه جعفر
966 المحدث الألباني خلاصة حكم المحدث صحيح في صحيح الجامع