His words, Exalted is He:

You can only warn him who follows the Remembrance, and fears the Compassionate One in secret…

He said:

The one who worships God in his innermost secret (sirr), will be endowed with certainty (yaqīn) by God. The one who worships God with a truthful tongue, will find his heart ascends to the very Throne.^{1lit. ‘his heart will not stop until it reaches the Throne.’} The one who worships God with equity (inṣāf),^{2Inṣāf can have the meaning of ‘doing justice to something’ or ‘giving it its due’.} will have the heavens and the earth weigh [in his favour].^{3lit. ‘in his scales’. That is, they will weigh in his favour on Judgement Day.}

He was asked, ‘What is equity (inṣāf) [in worship]?’ He replied:

It is that none of your bodily members moves unless it be for God. Furthermore, when you ask Him for the next day’s provision (rizq), your equity has left you, for the heart cannot bear two concerns (hammān).^{4In other words, if your mind is on your next day’s provision, it is not on God.} Equity between you and other people is when you take from them with the attitude that you are receiving a favour. However, if you demand to be treated justly, that means you are not being equitable.^{5This is because if someone receives something from another person, they should have the awareness that it has been destined for them by God. But if they demand something from others, then they are not having true trust in what He has planned for them.}

It was related of John the Baptist and Jesus عليه السلام that they went out walking, and John bumped into a woman, upon which Jesus said to him, ‘O son of my maternal aunt! Today you have committed a grave sin for which I do not think God will forgive you.’ He responded, ‘And what is that?’ He said, ‘You bumped into a woman.’ He said, ‘By God, I did not notice her.’ Jesus said ‘Glory be to God! Your body is with me but where is your heart?’ He said, ‘It is attached to the Throne, and if my heart were to find rest with the angel Gabriel عليه السلام for just a blinking of the eye, I would consider myself as not having known God, Mighty and Majestic is He.’

His words:

‘And why should I not worship the One who created Me…’ ^{1These words are said by a man unnamed in the Qurʾān who came from the furthest part of the city [36:20]. His warning to people that they should follow the messengers runs from vv. 20–25 of Sūrat Yā Sīn. Ṭabarī identifies him as Ḥabīb b. Marī, or according to one tradition, as Ḥabīb b. Zayd b. ʿĀṣim. In the Tafsīr al-Jalālayn he is said to have been a carpenter.}

He [Sahl] was asked about the best form of worship and replied:

It is sincerity (ikhlāṣ), in accordance with His words, And they were only commanded to worship God alone, devoting religion purely to Him (mukhliṣīna lahu al-dīn) [98:5]. No one’s actions become truly sincere, nor his worship whole, as long as he tries to evade four things: hunger (jūʿ), nakedness (ʿury), poverty (faqr) and abasement (dhilla). Indeed, God, Exalted is He, made his servants worship Him through the following three: the intellect (ʿaql), the spirit (rūḥ) and [physical] strength (quwwa). If he is afraid of [losing] two of these, the loss of intellect and the loss of the spirit, then he should take pains to perform well [the acts of worship]. As for [the loss of] physical strength, then there is no taking pains to perform them or learn them well, even if he prays seated.^{2The only apparent difference to note is that MS F638 has takallafa lahumā instead of takallafa lahā. Perhaps what is meant here is that a person can address any deficit or shortcomings in his intellectual and spiritual life through worship, while in the case of a loss of physical strength, it may not be possible to regain it.}

His words, Exalted is He:

If it had been Our will, We could have taken away their sight…

He said:

This means: ‘If We so willed We could gouge out the eyes of their hearts by which they perceived disbelief (kufr) and its path, so that they could only perceive Islam and nothing else.’ …but how would they have seen? the path of Islam if He did not do that.

His words:

…It is just a Reminder and a Qurʾān that makes things clear,

He said:

It is a reminder (dhikr) and a [source of] contemplation (tafakkur). But God, Glorified and Exalted is He, knows best.