What was the response of Ka'b b. 'Ujra to seeing Abd al-Rahman b. Umm Hakam delivering the sermon in a sitting posture, as mentioned in the hadith of the Prophet Muhammad (saw)?
 Ka'b b. 'Ujra reported that he entered the mosque and saw Abd al-Rahman b. Umm Hakam delivering the sermon in a sitting posture. Upon this he said:                      Look at this wretched person; he delivers the sermon while sitting, whereas Allah said:" And when they see merchandise or sport, they break away to it and leave thee standing."