The Prophet (peace and blessings of Allah be upon him) taught his Ummah the mandatory duties and religious rulings through both speech and action, and he clarified all of that in the most complete manner. Since prayer is among the most important obligations, he used to teach them how to perform it.In this Hadith, `Abdullah ibn `Abbas (may Allah be pleased with him) said: “I used to recognize the completion of the prayer of the Messenger of Allah (peace and blessings of Allah be upon him) by the Takbir.” That is, by his departure from the prayer. This indicates that his Taslim (ending salutation) was not always audible. The phrase “by the Takbir” means that when the Prophet (peace and blessings of Allah be upon him) completed the mandatory prayer and concluded it with the Taslim, he would glorify Allah and remember Him in a raised voice. This action is understood to have occurred either at specific times or during the early period of Islam, so that the people could learn the remembrance after the prayer. The Takbir mentioned here is not exclusive or limited to that alone, as other narrations indicate that the Prophet (peace and blessings of Allah be upon him) would also raise his voice with Tahlil (saying La ilaha illa Allah) and supplication (Du`a’) after the mandatory prayer..