LIARS NEED TO HAVE GOOD MEMORIES

IF OYU ARE A LIAR PERSON AND YOU ARE ALWAYS TELLING LIES YOU'D BETTER TO REMEMBER WHAT IS THE LIE YOU ARE TELLING, BECAUSE IF YOU DON'T DO IT, THEY WILL SPOT YOU. SO, LIARS NEED TO HAVE GOOD MEMORIES.
THAT IS NOT AN IDIOM, IT IS A QUOTE, ALGERNON SIDNEY CREATED IT. HE WAS AN ENGLISH POLITICIAN WHO WAS BEHEAD (DECAPITADO) ON 7 DECEMBER 1683.