Then the Prophet sallallaahu ‘alaihi wasallam laid his right hand above his left hand (crossed). He said:
“We, the prophets were ordered to immediately break and mengakhirkan dawn and put your right hand on the left hand (crossed) when doing the prayer.”
(Hadith narrated by Al-Imam Ibn Hibban and Adh Dhiya ‘with saheeh chain of transmission).
In a memoir he never passed a man who was praying, but this guy put his left hand on his right hand, then he let go, then the man put his right hand on his left hand. (Hadith reported by Ahmad and Abu Dawood with a saheeh isnaad).
Laying or holding
He sallallaahu ‘alaihi wasallam put your right arm on the back of his left hand, wrist and his left arm (see figure) based on the hadeeth of Wail bin Hujur:
“Then the Prophet sallallaahu ‘alaihi wasallam takbir then put his right hand in the palm of his left hand, left wrist or left arm.”
(Hadith narrated by Al-Imam Abu Dawud, Nasa’i, Ibn Khuzaimah, with a saheeh isnaad and also classed as saheeh by Ibn Hibban, hadith no. 485).
He also sometimes holding his left wrist with his right hand (see picture), based on the hadith Nasa’i and Daraquthni:
“But sometimes he stretched out his right hand fingers on his left arm.”
Folded across the chest
Folded hand on the chest is the right thing according to the sunnah based on the hadith:
“He put his hands on his chest.”
(Hadith narrated by Al-Imam Abu Dawud, Ibn Khuzaimah, Wail ibn Ahmad of Hujur).
Ways that fit this Sunnah by Imam Ishaq bin Rahawaih. Priest in the Book Masa’il Mawarzi, page 222 says: “hadith narrated by Imam Ishaq mutawatir to us …. He raised his hands when praying and doing qunut sebeluim qunut bowing. He menyedekapkan hand adjacent to the tits.” Such opinion was also expressed by Qadi ‘Iyadh al-Maliki in the last chapter in the Book of Prayer ash Mustahabatu Al I’lam, he said: “He put his right hand on the back of his left hand on his chest.”