"Lay down your life" is a phrase that conveys the sacrifice of one's life for a greater cause or for the benefit of others. There are several synonyms or similar phrases that can be used to express this idea, such as "give your life", "sacrifice yourself", "offer up your life", "lay your life on the line", "risk your life", "die for a cause", "fall in battle", "martyr yourself", and "make the ultimate sacrifice". These phrases are often used to honor and commemorate individuals who have selflessly given up their lives in service to their country, community, or cause.