surahs

Assalam-o-Alaikum, My question is about salat actually there are two. 1)When you get up from the ruku is it 'Rabbana-wa-lakalhamd" or "Rabbana lakalhamd". The reason for asking this question is that I have seen both in different instruction manuels. 2)Is it necessary to say the surahs during rakahs in the order the appear in the quran and without repetition or one is allowed to repeat surahs. For example if one has recited kawsar and ikhlas in fard can they be repeated in sunnah or not?

Discover the flexibility in reciting surahs during prayer, the importance of surah length, and the differing scholarly views on surah order. Learn how these affect the validity of Salah.