Leviticus 5:3-4

3or if he touches human uncleanness, of whatever sort the uncleanness may be with which one becomes unclean, and it is hidden from him, when he comes to know it, and realizes his guilt; 4or if anyone utters with his lips a rash oath to do evil or to do good, any sort of rash oath that people swear, and it is hidden from him, when he comes to know it, and he realizes his guilt in any of these;