When Imaam Maalik (rahimahullah) completed writing his Muwatta, he was greatly concerned as to whether he had written the kitaab with ikhlaas (complete sincerity).

In order to gauge whether the kitaab was written with ikhlaas, he asked Allah Ta‘ala to show him a sign. The sign that he wished to see is that if he places the kitaab in water, and if the ink of the pages does not wash off, then this will prove as a sign that he wrote the kitaab with ikhlaas.