Quran 35: 19-24 , which mean:
{ 19. Not equal are the blind [: the unbeliever] and the seeing man [: the believer,] a
20. the darkness b [: the ignorance] and the light c [: the knowledge],
21. the shade d and the torrid heat e;
22. Nor are the living equal f nor are the dead g.
God makes to hear whomsoever He will h, but you cannot make those in the graves to hear i.
23. You [Mohammed] are no other than a warner j.
24. We have sent you [Mohammed] with the truth [: the Quran, as] a bearer of glad tidings [of Paradise for believers] and as a warner [of punishment for disbelievers, associaters and the disobedient];
and there was not any [past misguided] nation k, but a warner l should have come to them.}
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a i.e. the unbeliever and the believer are not equal.
b i.e. the darkness in the nights of the lunar months are not alike; some of them are dark, and some have light. So the ‘darkness’ implies the ignorance, and the ‘light’ implies the guidance, and the ‘dark nights’ imply the past years when people were staggering in the darkness of ignorance, so they worshipped the idols.
And the ‘moon’ implies the guide and the messenger (or apostle) who invited them to worship God and forsake the idol worship, but they did not listen to his words until he set down with his death and departed from them.
c i.e. the light of the sun and the light of the moon are not equal. The ‘light’ implies the guide who guides his people to the way of the truth. The meaning: Not all the guides are equal: for We sent some of them to one tribe only and he could not guide them, and some of them We sent to his people alone, while We sent Mohammed to mankind as a whole.
The indication, that the guides and messengers (apostles) are not equal, is His saying – be glorified – in the Quran 17: 55, which means:
(We have preferred some prophets over others; and We gave to David the Psalms.)
d It means: The shade which you have in the life of the World is not equal to the shade which We have in Paradise; because the shade, which you have, disappears because of the earth spinning and because of the transition of the sun rays on it; while the shade which We have in the Gardens is fixed and does not disappear because the ground of the Garden or Paradise is stationary and does not rotate, and therefore, the shade in it is fixed [and is lasting.]
Moreover, the shade which you have is hot in summer and cold in winter, but the shade which We have is continuously optimum: neither hot nor cold.
Therefore, do not prefer the shade which you have to that which We have, and work for your Next Life in order to come to the shade which We have.
God – be glorified – said in the Quran 4: 57, which means:
(Therein, for them, shall be spouses purified [from menstruation and from all dirts], and We shall admit them to a [shelter of] persistent shade.)
e The ‘torrid heat’ is an implication of the chastisement; the meaning: The heat which you have in summer is not equal to the heat of Hell; so work for your Next Life and struggle for the cause of God, and forbear the heat of summer in order to be safe of the heat of Hell. The indication of this is His saying – be glorified – in the Quran 9: 81, which means:
(They said [to each other]: "Go not forth in the heat [of summer.]"
Say [Mohammed, to them]: "The fire of Hell is hotter", if only they could understand.)
f In their acts and struggling for the cause of God; the ‘living’ are the believers who responded to their Lord and to His messenger and they believed; but they are not equal in the work and the struggling for the cause of God: some of them struggled, and others lagged behind without struggling; so those ‘struggling’ are the ‘living’ in the neighborhood of their Lord; as in His saying – be glorified – in the Quran 2: 154, which means:
(And say not of those who are slain in God's way: 'They are dead.' No, but they are alive [by their souls], though you perceive [them] not.)
g The ‘dead’ implies the associaters because they lost their Next Life and lost their families; and even they are not equal: because some of them fought the Prophet, and some of them covenanted with him to peace and they did not fight him.
h i.e. He guides, to the Islam religion, the one who is worthy of the guidance.
i God – be glorified – likened the stubborn associaters to the spirits imprisoned in the graves; as such are the associaters bound with the traditions of their fathers.
j And you have warned.
k That were misguided away from the way of the truth.
l i.e. a guide to warn them of God’s punishment if they do not forsake the worship of idols and statues.
The interpretation is by Mohammed-Ali Hassan Al-Hilly.