EXOD421 It is fitting for a person to acknowledge and to show gratitude to those who have been kind to him. How base and disgusting it is if the recipient of kindness behaves as a stranger toward those who have been good to him. It is disgraceful to behave in an unappreciative manner. Each person must realize that he owes a tremendous debt of gratitude to his parents; not only did they bring him into the world; they also made great efforts for him in order to provide him with all of his needs during his childhood. Accordingly, one is truly obliged to honor one's parents and help them in every way possible. By performing this mitzvah, one becomes accustomed to display gratitude out of a true feeling of appreciation. As a result, one more easily senses a great debt of gratitude to Hashem, for He, too, brought us into the world. Hashem supplies us our needs all of our days. He bestows upon us a physical body that performs all of the functions necessary for life. More than that, Hashem gives us an intelligent and understanding soul. Were it not for the unique human soul that is breathed into our nostrils by Hashem Himself we would be as stupid and uncomprehending as horses, donkeys and the other beasts. If we reflect on this matter we will feel deep feelings of gratitude toward Him and will recognize the importance of dutifully serving Him.