…I am your [sincere] truthful advisor. Whoever is not sincere towards God within his own soul, and sincere towards Him with regard to His creatures, will be ruined. To act with sincerity (naṣīḥa) towards God’s creatures is more difficult than being sincere within one’s own soul. The lowest level of sincerity [towards God] within the soul is gratitude (shukr), which is not to disobey God by [abusing] the blessings He has bestowed [on you] (bi-niʿamihi).On another occasion I heard him say:Sincerity is not to involve yourself in anything which you do not have the power to put right.His words, Exalted is He: