Al-Matalib al-'Aliyah 486 — Placing the right hand on the left

It is narrated from Sayyiduna Abdullah bin Abbas (may Allah be pleased with them both) that the Messenger of Allah (peace and blessings be upon him) said: "We, the community of prophets, have been commanded to hasten our breaking of the fast (as soon as the sun sets), to delay our pre-dawn meal (suhur) (until shortly before its time ends), and to place our right hands on our left hands in the prayer." In the narration of Abd bin Humayd the wording is: "We, the community of prophets, have been commanded to delay our suhur and to hold our left hands with our (right) hands in the prayer."
This narration is gharib (unusual); Talhah bin Amr al-Makki alone narrated it, and there is weakness in the narrator. Furthermore, Ahmad bin Tahir bin Harmalah al-Tujibi reported something munkar (objectionable) in this chain: he said: My grandfather narrated to us, from Ibn Wahb, from Amr bin al-Harith, from Ata', from Sayyiduna Ibn Abbas (may Allah be pleased with them both), mentioning it. His saying "Amr bin al-Harith" is false and wrong, because in reality it is Talhah bin Amr. Moreover, Imam al-Daraqutni and other hadith scholars declared Ahmad bin Tahir a liar. Imam al-Tabarani recorded this narration in 'al-Mu'jam al-Awsat' through Ahmad bin Tahir himself.