In a video posted to the reality star's Instagram Story on Sunday, nine-year-old North, seven-year-old Saint, five-year-old Chicago, and four-year-old Psalm West shared messages for their mother. "Mom, I'm very grateful for you. I know I'm mean to you a lot and say you're nothing to me, but you mean the world to me," Saint said in his Mother's Day video message to Kim. "I love you more than anything." Kim shares her four children with ex-husband Kanye West. In the video, Saint wore a Yeezus shirt - referencing a nickname for his father.