Kitab-i-Iqan — Paragraph 53

Know verily that the purpose underlying all these symbolic terms and abstruse allusions, which emanate from the Revealers of God’s holy Cause, hath been to test and prove the peoples of the world; that thereby the earth of the pure and illuminated hearts may be known from the perishable and barren soil. From time immemorial such hath been the way of God amidst His creatures, and to this testify the records of the sacred books.