What is the ruling on raising hands for supplication after standing up from Rukoo‘ (bowing down) to say "Sami‘a Allaahu liman hamidah (May Allaah Answer he who praises Him)" by the Imaam and saying "Rabbanaa wa lakal-hamd (Our Lord, for You is all Praise)" by those praying behind him?

All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His Slave and Messenger.

It is recommended to raise the hands after standing up from Rukoo‘. It was narrated on the authority of Ibn ‘Umar that he said: "I saw the Prophet, sallallaahu ‘alayhi wa sallam, begin the prayer by saying Takbeer (saying: Allaahu Akbar) and he raised his hands until they were in line with his shoulders. When he said Takbeer for Rukoo‘ he did the same, and when he stood up from Rukoo‘ he did the same and said 'Sami‘a Allaahu liman hamidah' and 'Rabbanaa wa lakal-hamd' ..."  [Al-Bukhari, Muslim and others]

This means that the hands are raised for standing up from Rukoo‘. Raising hands for supplication should not be done except when one says Qunoot (a type of supplication), according to the preponderant opinion. This is the opinion of the Hanbali, Shaafi‘i and Hanafi scholars .