April 6

But let us be on our guard—so the Master continually reminds us from His Station on high—lest too much concern in that which is secondary in importance, and too long a preoccupation with the details of our affairs and activities, make us neglectful of the most essential, the most urgent of all our obligations, namely, to bury our cares and teach the Cause, delivering far and wide this Message of Salvation to a sorely-stricken world. 
(Shoghi Effendi, from a letter dated March 12, 1923; ‘Baha’i Administration’)