The motto of preaching shall always be aimed at the ultimate goal of life. The ultimate goal of life is to re-establish our lost relation with Godhead who is the Absolute Whole, and we all living entities are His parts & parcels.
We have forgotten our relation with Godhead from time immemorial by somehow or other & due to our forgetfulness of the relation, we are roaming life after life in different species of bodies which are 84 lacs in number. This process of transmigration from one body to another after death is a __ of disease of the living entity & the chance of curing the disease is possible very effectively in this human form of life.