"The Soul should always stand ajar
That if the Heaven inquire
He will not be obliged to wait
Or shy of troubling Her

Depart, before the Host have slid
The Bolt unto the Door --
To search for the accomplished Guest,
Her Visitor, no more --”

Emily Dickinson Poem 806. Also, from page 5 of 'How To Change Your Mind' by Michael Pollan.