Swami Vivekananda epistle...

I like to work on calmly and silently, and the Lord is always with me.
Follow me, if you will, by being intensely sincere, perfectly
unselfish, and above all, by being perfectly pure. My blessings go
with you.

From Chicago: January 11, 1895. Letter to G. G. Narasimhachariar.
Complete Works, 5: 65