While Allah is closer to us than our jugular vein ((We are nearer to him than his jugular vein)); and He can satisfy all our needs at once. What do we need invocation (Tawasul) for? What are its effects and merits? The present writing answers the questions. This analysis clarifies that if invocation is carried out under certain circumstances mentioned in The Holy Quran and Tradition, it causes proximity to Allah and attraction of spiritual blessings and forgiveness of the sins. The ones who deny invocation are deprived of all these merits and effects. Being ignorant of the importance and merits of invocation, they pose such questions. Hence this writing mentions some of the merits and effects of Tawasul.