Shama-il Tirmidhi Chapter 25, Hadith Number 30 (172).

Hazrat Umme Munzir radiyallahu anha says, Rasoolullah sallallahu alaihe wasallam visited me. Hazrat Ali radiyallahu anhu was with him. We had some bunches of dates hanging. Rasoolullah sallallahu alaihe wasallam began eating from them. Hazrat Ali radiyallahu anhu also began eating with him. Rasoolullah sallallahu alaihe wasallam stopped him saying, ‘You have just recovered from your illness and should not eat this.’ He (Ali radiyallahu anhu) stopped and Rasoolullah sallallahu alaihe wasallam continued eating. Hazrat Umme Munzir radiyallahu anha says, I then cooked some barley and beetroot. Rasoolullah sallallahu alaihe wasallam said to Hazrat Ali radiyallahu anhu, ‘Eat this, it is suitable for you.

Commentary.
From this hadith we derive that to give consideration to the asbaab (causes) is not against tawakkul (complete faith and reliance in Allah). This has been discussed in detail in (Imam Ghazali’s) Ihyaa-ul-Uloom. Those who wish may refer to it there.