A Vaishnava wants to see others happy and free from anxiety. We should always try to faithfully serve Vaishnavas by spreading the glories of Krishna consciousness for the welfare of others. This was the mission of our previous acaryas. Service to Vaishnavas is real service to Krishna. Vaishnavas are para-dukha-dukhi—they see others’ anxieties as their own. Thus, to serve Vaishnavas, we must think of how we can relieve their anxieties that they have taken on behalf of others who are suffering. We can see why Srila Prabhupada always wanted us to strongly and vigorously preach Krisana consciousness. By doing this, we will please Srila Prabhupada, Srila Bhaktisiddhanta and our entire guru-parampara. We will relieve the anxieties of others and we will see that our own anxieties will also go away. Prabhupada said that when you take care of others, Krishna will take care of you. When you help others to become Krishna conscious, you become Krishna conscious yourself.
Lectures from a disciple 3, Pg 349, last Paragraph