What is the opinion regarding Ibn al-Jawzi's book "Sayd al-Khatir," and what is the opinion regarding the thought/reflection "Causes and Effects" which states that Allah punishes His awliya (saints/devout servants) and those who know Him if their hearts incline towards causes (material means)?

The book "Sayd al-Khatir" is good in the chapter of conduct and purification of the soul. Sheikh Ibn al-Jawzi does not deny taking means, rather he believes that it is a path that must be followed, but he disapproved of the heart's attachment to them. True reliance (tawakkul) is the rejection of means from the heart, not from the limbs, as Ibn al-Qayyim said: "Reliance is not complete except by rejecting means from the heart, while the limbs are engaged with them, so one is disconnected from them [in heart] yet connected to them [in action]."

And Allah's jealousy over the hearts of the gnostics, and that He may punish them if they turn away from perfect reliance on Him to return to Him, has a general validity.