Kṛṣṇa says, mattaḥ parataraṁ nānyat kiñcid asti dhanañjaya (BG 7.7), so we have to carry these words that, "The Supreme Personality of Godhead is Kṛṣṇa." Where is the difficulty? It is authorized. Kṛṣṇa says, and we simply carry the words. So where is difficulty? So simply by carrying these words that, "Kṛṣṇa is the Supreme Personality of Godhead. He wants that you surrender unto Him."
So any child can carry these words. Any foolish man can carry these words. And if you do that, Caitanya Mahāprabhu says, then you become guru, simply by carrying these words. Āmāra ājñāya guru hañā tāra' ei deśa (CC Madhya 7.128). Even in your village, in your home, you can say to your wife, to your children. They will accept you that, "Kṛṣṇa is the Supreme Personality of Godhead." Then you become guru at home. Where is the difficulty? Is there any difficulty? But people will not do that. This truth they will not say. What is the reason? Say what is the reason why they do not carry this message, simply to say everyone, whomever you meet. You are meeting daily with your wife, to your children, your friends. If you simply do this missionary work and say that, "Kṛṣṇa is the Supreme Personality," then you become a great devotee. You become a guru.