We have to chant ourself offenselessly, and if somebody hears my offenseless chanting, it will gradually be effective for the persons who are hearing. Śravaṇaṁ kīrtanaṁ (SB 7.5.23). The process is one should chant and one should hear. That we follow. Somebody leads by chanting, and others follow. So if the chanter is pure, then the chanting will be effective. If the chanter is impure, then it will not be effective. But still we should go on.
And another thing is that while chanting Hare Kṛṣṇa mantra, if we are still attached to material attraction, that is also offense. The whole process is to become disgusted with material things. Vīta-rāga. Kṛṣṇa consciousness movement means we, all conditioned soul, we have come to this material world just to enjoy sense gratification independently. This is our main disease. Everyone in this material world is trying his best how to satisfy the senses. This is the material disease. And Kṛṣṇa consciousness movement means how to cure this material disease and go back to home, back to Godhead. Unless we cure our material disease, it is not possible to go back to home, back to Godhead. So we must be disinfected. This is the real process. So we have to taste it. Bhaktiḥ pareśānubhavo viraktir anyatra syāt (SB 11.2.42). Advancement of material . . . and devotional service means proportionately we become detached to material attraction.