Imām Ibn Al-Qayyim [d. 751 AH] said:

Positive thinking [concerning Allāh] should take the form of possessing hope [of reward for the completion of good deeds]. So, if positive thinking encourages a person to engage in acts of obedience and dissuades him from misdeeds, then this is true unadulterated hopefulness [in Allāh]. Comparatively, whomever allows himself to be idle and inactive but remains hopeful [of reward]; and claims hopefulness while being lethargic [regarding obedient acts], careless of engaging in acts of disobedience, [he should know] that he has been deceived. For if a man possesses a piece of land from which he hopes to profit from its fertile soil what will be of benefit to him but he carelessly ignores it; he does not plant seeds in it, nor does he till that soil all the while possessing a positive outlook that fertile [products] shall come to him of the ilk of one who actually plants, tills, waters the land, and spends time in its cultivation— he would be counted by the people as the most foolish of fools. Similarly, if he was to possess a positive attitude and strong hope concerning being granted the boon of children but without engaging in sexual intercourse, or to become the most knowledgeable scholar of his time but without seeking knowledge or focussing his aspirations on that goal, and the like of [these examples].

Such is the case concerning the one who possesses a positive attitude and strong hope of the achievement of success with the highest of stations [in Jannah] and blissful, perpetual enjoyment [in it], but yet he does not engage in acts of obedience, or seek to gain closeness to Allāh through enacting His orders and refraining from that which He has forbidden. And with Allāh is true guidance [towards knowledge and action]. The Most High has said:

إِنَّ الَّذِينَ آمَنُوا وَالَّذِينَ هَاجَرُوا وَجَاهَدُوا فِي سَبِيلِ اللَّهِ أُولَٰئِكَ يَرْجُونَ رَحْمَتَ اللَّهِ ۚ وَاللَّهُ غَفُورٌ رَّحِيمٌ ‎﴿٢١٨﴾

‏‘Indeed, those who have believed and those who have emigrated and fought in the cause of Allāh – those expect the mercy of Allāh. And Allāh is Forgiving and Merciful.’
[Al-Baqarah, 2: 218]

So contemplate the way [Allāh] has made their hope [expectation of mercy] the very same as their enacting those acts of obedience!

While those deep in self-deception will say:

The careless ones who discard the rights of Allāh as if they are non-existent, who nullify His commands, act unjustly regarding His servants, who dare to engage in that which He has made unlawful, they are the ones who truly hope for the mercy of Allāh!

The very heart of this issue and its innermost secret is that hope and positive thinking only go hand-in-hand with the execution of the means through which the wisdom of Allāh in his judgments and His Divine Predestination and reward and bounties can all be fulfilled. So the slave [of Allāh] executes the means [acts of obedience], then he thinks positively concerning his Lord, while hoping that He does not allow himself to be completely reliant on his [own actions]. Rather, he hopes they will allow him to reach that which is beneficial to him while deterring from that which is its antithesis, simultaneously removing its harmful effects.

Source: Al-Dāʾ wa-al-Dawāʾ: 86-87
Translated by: Riyāḍ al-Kanadī