A soap molecule because of its combination of carbon, oxygen, and hydrogen atoms will have a composition that attracts water at one end (water loving) and dirt and oil at the other (hydrophobic).  Water on its own will not remove dirt and oils because it forms bead on fabric or skin through surface tension.  The molecules are attracted to each other and will hold together “cohesion” resisting being absorbed into the skin or fabric.  Soap reduces the surface tension of the water and allows it to be absorbed into the skin and or fabric where the soap can attach its water loving end to the water and “suck” the dirt and grease from the skin with its oil loving end (hydrophobic), allowing the dirt and oil laden droplets to be rinsed down the drain.