Q: Why does one have to leave two surahs in between when praying salaah? If I only leave one surah in between do I have to repeat my salaah?
A: When one leaves out a surah in between two suras, it would seem as if one deemed that surah insignificant. Therefore, the Jurists of Islam have termed this practice makrooh (disliked or disapproved). However, the salah does not have to be repeated. This rule only applies when the surah left out is shorter than the other two. If it is a big surah then there is no harm in leaving it out and reading the surah after it.
Mufti Siraj Desai