The word 履行 is formed by combining two characters, each contributing a layer of meaning to create a unified concept. 履 originally depicts the act of treading or walking upon something, often associated with shoes or footsteps. 行 fundamentally means to walk, go, or proceed. When combined, the imagery is of "walking in the footsteps of" or "treading the path of", which evolved metaphorically to mean carrying out or fulfilling one's duties, promises, or obligations as if steadily walking the required course.