It is narrated from Hazrat Mu'adh (may Allah be pleased with him) that when the Noble Prophet (peace and blessings be upon him) sent him towards Yemen, he asked him, "If a decision comes before you, how will you resolve it?" He replied, "I will decide it in the light of the Book of Allah." The Noble Prophet (peace and blessings be upon him) asked, "If you do not find it in the Book of Allah, then what will you do?" He replied, "Then I will decide in the light of the Sunnah of the Noble Prophet (peace and blessings be upon him)." The Noble Prophet (peace and blessings be upon him) asked, "If you do not find its ruling in my Sunnah either, then what will you do?" He replied, "Then I will exercise ijtihad with my own opinion and I will not fall short in it in any way." Upon this, the Noble Prophet (peace and blessings be upon him) struck his blessed hand on my chest and said, "All praise is due to Allah who has guided the messenger of His Messenger to that which pleases His Messenger."