Fiqh-us-Sunnah Volume 1, Purification and Prayer, Fiqh 1.149.

It is preferred for the one who is praying, whether he be the imam, follower or praying by himself, to say, “Allah hears him who praises Him,” upon coming up from the bowing. When he is standing straight, he should say, “Our Lord, and to You is the praise,” or “O Allah, Our Lord, and to You is the praise.” Abu Hurairah reported that when the Prophet, upon whom be peace, rose from bowing he would say, “Allah hears him who praises Him,” and while standing (straight) he would say, “Our Lord, and to You is the praise.” (Related by Ahmad, al-Bukhari and Muslim.)

Al-Bukhari records in the hadith from Anas, “When he says, ‘Allah hears him who praises Him,’ you say, ‘O Allah, our Lord, and to You is the praise.” Ahmad and others record a hadith from Abu Hurairah in which the Prophet, upon whom be peace, is quoted as saying, “When the imam says, ‘Allah hears him who praises Him,’ you say, ‘O Allah, our Lord, and to You is the praise.’ If one’s statement corresponds to that of the angels, all of his previous sins will be forgiven.” The Prophet said, “Pray as you have seen me pray.” This applies to all of his glorifying and praise statements, even if the person is following the imam. The answer to those who say, ‘One should not combine both of these sayings’ (‘Allah hears him…’ and ‘O Allah, our Lord…’) but only say the one of praise, has been given by an-Nawawi who said, “Our companions say that the mentioning of the command, ‘And you should say, O Allah, our Lord…’ is in conjunction with ‘Allah hears him who praises him.’ But the Prophet, upon whom be peace, only mentioned the statement, ‘O Allah, Our Lord, to you is the praise,’ because they had already heard the statement, ‘Allah hears him who praises Him’ aloud from him. It was his sunnah to say that phrase aloud, but they did not hear him say, ‘Our Lord, to You is the praise’ because he said it in a subdued voice. They knew the Prophet’s words, ‘Pray as you have seen me pray,’ and knew that it was to be taken in the general sense without any restrictions. They used to say, ‘Allah hears him who praises Him,’ and therefore there was no need for the Prophet, upon whom be peace, to order them to say it again. But they did not know, ‘Our Lord, to You is the praise,’ and therefore he ordered them to say it.”

The two phrases are the least that one should say while standing. But one may add any of the supplicatory words mentioned in the following hadith:

1. Said Raf ah ibn Rafa’, “One day we prayed behind the Messenger of Allah, upon whom be peace. When he raised his head from bowing, he said, ‘Allah hears him who praises Him,’ and a man behind him said, ‘Our Lord, to You is the praise, as much as it can be and as blessed as it can be.’ When the Prophet, upon whom be peace, finished the prayer he said, ‘Who said that phrase earlier?’ A man said, ‘I did, O Messenger of Allah.’ The Prophet said, ‘I saw more than thirty angels chasing after you to see who would record it first.”‘ (Related by Ahmad, al-Bukhari, Malik and Abu Dawud.)

2. ‘Ali reported that when the Prophet raised his head from bowing he would say, “Allah hears him who praises Him, and to You is the praise filling up the heavens and the earth, what is between them and filling up whatever You wish in addition to that.” (Related by Ahmad, Muslim, Abu Dawud and at-Tirmizhi.)

3. ‘Abdullah ibn Abu ‘Aufa reported that when the Prophet raised his head from bowing he would say, “O Allah, to You is the praise filling up the skies and the earth and filling up whatever You wish in addition to that. O Allah, purify me with snow, hail and cold water. O Allah, purify me from sins and cleanse me from them as one cleans a white garment from filth.” (Related by Ahmad, Muslim, Abu Dawud and Ibn Majah.)

4. Said Abu Sa’eed al-Khudri, “When the Prophet, upon whom be peace, would say, ‘Allah hears him who praises Him,’ he would (also) say, ‘O Allah, to You is the praise filling up the skies and the earth, and filling up what You wish in addition to that. You are the One who is worthy of praise and glory. This is the most correct statement that a slave could make. And we are all slaves unto You. There is no one who can prevent what You have given. And there is no one who can give what You have prevented. No one can benefit from fortune (in the face of) Your fortune.”‘ (Related by Muslim, Ahmad and Abu Dawud.)

5. It has also been authentically reported from the Prophet, upon whom be peace, that after saying “Allah hears him who praises Him,” he would say, “To my Lord is the praise, to my Lord is the praise,” until he would be standing for as long as he was bowing.