In plain words
The world of today is filled with unrest. Because so many evil sounds enter the atmosphere, nothing but evil thoughts arise in everyone. If good feelings are to arise in man, the atmosphere must be pure. As the fire is, so is the smoke. As the smoke is, so is the cloud. As the cloud is, so is the rain. As the rain is, so is the crop. As the crop is, so is the cooking. As the cooking is, so are the thoughts. So the root cause of our thoughts is the very food we eat. This food depends on the atmosphere. This atmosphere depends on man's conduct. “The fig, to look at, is all gold; open its belly and look, and it is full of worms.” To look at, they all seem nothing but devotees. But open the heart and look: nothing but worms! So first of all we must make the atmosphere of the heart pure. For this, nāmasmaraṇa is vital. The Name is very precious, lofty and holy. The purer the feeling with which we utter the Name, the purer the atmosphere becomes. The bhajans we sing must purify the atmosphere. Before we purify the atmosphere outside, we must purify our own heart. God is a lover of song, one who delights in song. That is why, they say, Tumburu and Nārada sing without ceasing before Nārāyaṇa. In the world a great many poets weave verses and write kāvyas. But God is not absorbed in anything else as He is absorbed in song. So you must sing bhajans in such a way that they draw the heart. Only when you forget yourselves and sing does it draw the heart. So those who sing bhajans must first of all fill their hearts with Prema. When you sing bhajans with a pure heart, the whole world becomes pure.
What should a bhajan be like?
What is saṅkīrtana? “Samyak kīrtanaṃ iti saṅkīrtanaṃ.” It must melt the heart and move it. Only then can everyone receive Ānanda. So if in bhajan you look only to pitch, rhythm and tune, there is no gain. You must open your heart and sing. Those who lead the bhajan must recognise one more thing as well. When you sing bhajans, many thousands are listening. So you must sing songs that everyone can follow easily. You must not forget that many thousands are around you. If you sing some great long kīrtanas or other, no one can follow. Because they cannot follow, discouragement sets in among them. In the end the very mention of bhajans brings on weariness. So you must sing songs made of short names such as Rāma, Kṛṣṇa, Govinda, Allah and Jesus. Then everyone will be able to follow easily. In bhajan, do not use words like long, long well ropes. When you are alone in your house, sing whatever you please. But when ten people gather, the song you sing must be such that everyone understands it.