On the authority of Jaabir radiyAllahu 'anhu said: The Messenger of Allah used to teach us al-istikhaarah regarding all affairs as he would teach us a suurah from the Qur'aan, saying; 'If any amongst you intends to undertake any affair then let him preform two units of prayer excluding the obligotary prayers then let him say:'o Allah! I seek Your counsel by Your knowledge and by Your power I seek strength...[Reported by Imaam Bukhaaree, Kitaab al-Da'awaat no. 6382]

The 'ulamaa [scholars] have differed amongst themselves, do you favour al-istikhaarah or al-istishaarah? [consultation]

The correct opinion is that al-istikhaarah is to be favoured above al-istishaarah, because of the hadeeth of the Prophet that was mentioned above, then after having repeated the istikhaarah three times and it is still not clear to you [i.e you have not reached a decision] then you resort to al-istishaarah [consultation] and what you are adviced on you follow.

When I said the istikhaarah should be repeated three times then this is from the sunnah of the Prophet that when he made du'aa [invocation] he used to repeat it three times. Istikhaarah is du'aa, so it will be made clear to you the first time or the second or the third, and if it is not made clear to you [i.e what decision you should make] then you resort to al-istishaarah.