and when ibrahim said my lord! show me how you will give life to the dead he said are you not certain ? ibrahim said surely yes why not? but because i wish to put my heart at ease he said therefore take four birds and cause them to become familiar to you then place a part of each of them on separate hills then call them – they will come running towards you and know well that allah is almighty wise. 
وإذ قال إبراهيم رب أرني كيف تحيي الموتى قال أولم تؤمن قال بلى ولكن ليطمئن قلبي قال فخذ أربعة من الطير فصرهن إليك ثم اجعل على كل جبل منهن جزءا ثم ادعهن يأتينك سعيا واعلم أن الله عزيز حكيم