Allaah Bound Tawakkul with Eemaan’ by Imaam Ibnul Qayyim
Allaah (The Most High) said:
اللَّهُ لَا إِلَٰهَ إِلَّا هُوَ ۚ وَعَلَى اللَّهِ فَلْيَتَوَكَّلِ الْمُؤْمِنُونَ
The strength of one’s Tawakkul (i.e. reliance upon Allaah) or its weakness depends on the strength or weakness of (his or her) Eemaan. Whenever the Eemaan of a slave of (Allaah) is strengthened, his (or her) Tawakkul is stronger. And when (one’s) Eemaan is weak, (his or her) Tawakkul becomes weak. And when (one’s) Tawakkul becomes weak, it is proof that (his or her) Eemaan is weak and that has to be the case. Allaah (The Most High) bound Tawakkul with Ibaadah; Tawakkul with Eemaan; Tawakkul with Islaam; Tawakkul with Taqwaa and Tawakkul with Hidaayah (i.e. guidance).
[Source: Badaa’i At-Tafseer Limaa Fassarahu Al-Imaam Ibnul Qayyim’ Vol 3, page 159…abridged and slightly paraphrased]