Imam Malik (رحمه الله تعالى) said: “He who gains knowledge in jurisprudence (fiqh) without tasawwuf then he will certainly become corrupt (fisq), and he who practices tasawwuf without gaining knowledge in jurisprudence will become a heretic (tazandaqa), and he who gathers between the two has proven true (tahaqqaq).”
Source: Hashiya of al-Adawi upon imam al-Zurqani’s commentary on the Izziyya in Maliki fiqh: 3/195, and the commentary on Ayn al-Ilm wa Zayn al-Hilm by Imam Mullah Ali al-Qari: 1/33.

