Once a man took some medicine that could apparently prevent death to the King of the Chu Kingdom. The official at the entrance of the palace took the medicine inside the palace but was stopped along the way by one of the king's personal guards. The guard asked the official, "What are you carrying ?" "Death preventing medicine," the official replied, "You eat it and you won't die." The guard immediately grabbed and swallowed the medicine in one gulp.
When the king heard of this he was furious, and sent for the guard. The guard come before the king and tried to plea his case. "Since a stranger offered this antideath medicine, if I had of died, when I ate the medicine, then it would have shown that it was actually an attemtp to poison you. If you kill me, it shows everyone that you are prepared to be fooled. You should release me for your reputation as a benevolent and wise king." The king thought there was some truth to his words and didn't kill him.
When someone offers or claims something, he or she must have certain motives. It could be good and sincere motives, but it can also turn out to be bad or negative motives. We should be aware to validate those motives, especially when he claims something that we know we want to believe. Validation is very important to prevent us being trapped into deceptions and the simplest form of validation is to validate his claims by putting his statements into action and observe the result.