Anyone can become a guru by simply preaching that Krishna is the Supreme Personality of Godhead.Listen — Srila Prabhupada Uvaca
Prabhupāda: ...there will be proper rainfall. And if there is proper rainfall, then you get sufficient food grains; not only food grains, other things also. Sarva-dughā mahī, sarva-kāma-dughā mahī [SB 1.10.4]. From the earth you can get all the necessities of life. Actually you are getting food grains, minerals, trees, fruits, flowers, everything from the earth.
Sarva-dughā, sarva-kāma-dughā mahī. This mahī, when it is soaked with proper rains, it becomes fertile. Therefore we have to depend on the rainfall. There is one verse in Śrīmad-Bhāgavatam, kāmaṁ vavarṣa parjanyaḥ [SB 1.10.4].
Parjanya means rainfall. Rainfall means it is supplying all the necessities of life. And this rainfall will be easy when there is yajña. And nobody is performing yajña; therefore nowadays rainfall is scarcity.
In Europe recently I have seen, there is no rainfall, whole Europe. It is on the verge of drying everything. So this punishment will come in this Kali-yuga. There will be no rainfall, and there will be not sufficient food supply, and the government will simply levy taxes on different pleas, and people will be so much embarrassed that they will give up their hearth and home and flee away to the forest.
It is stated. So therefore you must perform yajña. And that is very easy in this age. Yajñaiḥ saṅkīrtana-prāyair yajanti hi su-medhasaḥ [SB 11.5.32].
You cannot perform the former yajñasa by sacrifice tons of ghee and grains because you have no sufficient food grains even. But still, if you chant this saṅkīrtana, that is yajña. Therefore you must take to saṅkīrtana-yajña. Yajñaiḥ saṅkīrtana-prāyair yajanti hi su-medhasaḥ.
It is very easy. [break] ...the duty of human being, prāṇaiḥ, with life; arthaiḥ, with money; dhiyā, with intelligence; and vācā, by words. If one sacrifices his life for Kṛṣṇa's cause, then it is first-class. If he cannot sacrifice his life for Kṛṣṇa he can contribute his hard-earned money for Kṛṣṇa. If he cannot do so—if he has no money—he can give some intelligence.