Hold the holy things close to you.

Matthew 7:6 Do not give what is holy to the dogs; nor cast your pearls before swine, lest they trample them under their feet, and turn and tear you in pieces.

Pigs will consume anything with no regards. Jesus, in the context of judging righteously, says do not give up your holy things (those things from God) to dogs or cast them out before pigs (unbelievers). They dont care about the revelations God has shown you. They dont care for Gods resources. This isnt saying that we shouldnt reach out to the unbeliever at all. For then how would we have came to Jesus. The gospel of Christ is the simple message the world needs to hear and challenged by. The intimate deep truths God reveals to us isnt for the unbeliever. They treat them like Esau treated his birthright. He disregarded it for a bowl of stew. Cant clean the fish until you catch the fish.