How can one recognize a mesenger from Vaikuṇṭha, and how can one determine whether the message is real or false?

If my prayer is genuine, then I will understand everything by the mercy of the omniscient Lord. A student can recognize a learned scholar only by the learned scholar’s mercy. The Lord in my heart will help me. I need only to depend on him. There are only two ways to know anything in this world. The first is to try to understand with the help of our material experience, and the second is to receive knowledge through aural reception from an exalted personality coming from the kingdom of knowledge. To receive knowledge by this second method we must be prepared to fully surrender to that exalted personality.