There is a longing inside of us, one that C.S. Lewis referred to when he wrote: "If I find in myself a desire which no experience in this world can satisfy, the most probable explanation is that I was made for another world." This longing was designed to be satisfied by God. When we are not satisfied with God, we will most assuredly fill that vacuum with something else. When we are not decidedly and deliberately pursuing God with all our heart, we open the door to sin.