When someone gives their testimony, it means that they are telling others what they have experienced and what they believe to be true. Think of it like telling a story about something that happened to you. Testimony can be really important in places like court, where people need to share what they saw or heard to help figure out who is telling the truth. Testimony can also be religious, where people talk about their beliefs and experiences with their faith. It's sort of like sharing your own personal story to help others understand what you believe in.