What are the instances in prayer when one should raise the hands to the ears, and what is the ruling on one who raises them with every takbeer versus one who raises them only with the takbeerat al-ihram?

It is desirable to raise the hands in prayer at the opening takbir (takbirat al-ihram), when bowing, when rising from bowing, and when standing up for the third rak'ah. Some scholars have gone further, believing it is permissible to raise the hands at every takbir. Whoever does not raise their hands except at the opening takbir has deviated from the Sunnah, but their prayer is still valid, because raising the hands is a desirable Sunnah, not an obligation.