Al-Matalib al-'Aliyah 450 — The opening supplication and other matters

It is narrated from Sayyiduna Abdullah bin Zayd (may Allah be pleased with him) that the Prophet (peace and blessings be upon him) said: "The opening of the prayer (that is, its basic and necessary condition) is purification and ablution; its tahrim (that is, the act by which a person cuts himself off from worldly occupations and enters the special sanctity of the prayer) is saying the opening takbir (takbirat al-ihram); and its tahlil (that is, the act by which the restrictions of the prayer end and the servant comes out of the prayer) is saying the salam."
Imam al-Harith bin Abi Usamah recorded it in his Musnad. Its chain contains Muhammad bin Umar al-Waqidi, who is da'if (weak) according to the majority; however, this hadith has many supporting narrations (shawahid) from other Companions, including Sayyiduna Ali and Sayyiduna Jabir (may Allah be pleased with them), on the basis of which this narration reaches the grade of sahih li-ghayrihi (authentic due to supporting narrations), and it is also found in the four Sunan with different wordings.