What is the ruling on placing the hands after rising from rukūʿ?

The scholars have differed regarding placing the right hand over the left after bowing (ruku'): - Some consider it sunnah due to the generality of the hadith of Sahl ibn Sa'd al-Sa'idi: "The people were commanded that a man should place his right hand on his left forearm in prayer," and that standing (qiyam) includes what precedes it and what follows it. Also, because the natural position for the hands during standing is on the chest, and this is further from fidgeting. - Others consider it not prescribed due to the absence of a specific text, and that the standing after bowing is an upright posture (i'tidal) and not a full standing (qiyam), so the worshipper should let his hands hang down. - And some gave a choice between placing them and not placing them, and this is what Imam Ahmad said.

The first opinion is the most preferred. The prayer is valid with both actions, and this difference should not lead to dispute, or declaring it an innovation, or abandoning the Sunnah.