Is it obligatory to line up hands with ears or shoulders in prostation?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

The Sunnah in prostration is that the worshipper places his hands parallel to his shoulders, or places them parallel to his head so that his head will be between his hands; there is evidence about all of this in the Sunnah.

With regard to putting one’s hands parallel to one’s shoulders, Abu Hameed as-Saa’idi narrated about the method of the prayer of the Prophet that “When he prostrated, he placed his nose and his forehead on the ground, and he held his forearms away from his sides, and he placed his hands parallel to his shoulders.” [Abu Daawood and at-Tirmithi]

As regards putting one’s head between one’s hands, then Waa’il ibn Hajar narrated about the method of the prayer of the Prophet that “When he prostrated, he placed his forehead on the ground between his two palms.” [Muslim]

Also, the Hadeeth of al-Baraa’ ibn Aazib reads: "When the Prophet prostrated, he placed his face between his hands.” [Muslim]

Tuhfatul-ahwadhi reads:

“The scholars differed in opinion in regard to these two different narrations of the Hadeeth, and other Ahadeeth in the same meaning, so some of them acted according to the Hadeeth of al-Baraa’ and upon other Ahadeeth in the same meaning, and some of them acted according to the Hadeeth of Abu Hameed and upon other Ahadeeth in the same meaning, and all this is permissible and confirmed (authentic).” [End of quote]

These are desirable acts of the prayer and not among its Waajibaat (obligations) as stated by the scholars.

Allah knows best.