You think because you understand 'one' you must also understand 'two', because one and one make two. But you must also understand 'and'.
RumiWhen you resolve to become pious, the devil in your nature cries out at you, "Tread not those paths, O confused one; distress and poverty will overcome you. You will be despised, let down by friends, you will regret it." Dread of the devil has bound their souls; the cries of the devil are the drover of the damned; the call of the Lord is a guardian of the saints.
Rumi