Islam had remarkable growth during its first 150 years. These came primarily as a result of military conquests.Fatihah wrote: The Muslims fought in defense. And when the weapon of choice by the attacker is a sword, than it is very logical that one should use a sword in defense, and self-defense does not contradict one's intent for peace.
Light Expansion under Muhammad, 622–632/A.H. 1-11
Medium Expansion during the Rashidun Caliphate, 632–661/A.H. 11-40
Dark Expansion during the Umayyad Caliphate, 661–750/A.H. 40-129
Question for debate: were these conquests the result of purely defensive wars?