‘Sun’ is often applied allegorically in scripture in reference to God, the devil and man. Each of the following articles explores this idea further.
Recommended reading:
The Devil – The light of Darkness
When the heat of the sun/day is spoken of, whether it’s the heat of God’s sun or that of the devil, the heat brings death. The heat of God’s sun brings death to the flesh, whilst the heat of the devil’s light brings death to the spirit i.e. separation from God.
The heat of the sun of righteousness:

For the sun is no sooner risen with a burning heat, but it withereth the grass, and the flower thereof falleth, and the grace of the fashion of it perisheth: so also shall the rich man fade away in his ways.
James 1:11 KJV
The sun that rose with the burning heat is Christ:
But unto you that fear my name shall the Sun of righteousness arise with healing in his wings; and ye shall go forth, and grow up as calves of the stall.
Malachi 4:2 KJV
He came to shine the light of God’s love upon all men:
That ye may be the children of your Father which is in heaven: for he maketh his sun to rise on the evil and on the good, and sendeth rain on the just and on the unjust.
Matthew 5:45 KJV
The grass and the flower of it, which withers and die due to the burning heat of the sun of righteousness, are biblically synonymous with flesh and the works of it:
The voice said, Cry. And he said, What shall I cry? All flesh is grass, and all the goodliness thereof is as the flower of the field: [7] The grass withereth, the flower fadeth: because the spirit of the LORD bloweth upon it: surely the people is grass.
Isaiah 40:6-7 KJV
The goodliness of a thing is effectively what that thing is good for. The goodliness of a tomato plant is that it produces tomatoes. The goodliness of salt is the savour. Hence Jesus’s words:
Ye are the salt of the earth: but if the salt have lost his savour, wherewith shall it be salted? it is thenceforth good for nothing, but to be cast out, and to be trodden under foot of men.
Matthew 5:13 KJV
Grass and the goodliness thereof is therefore flesh and the works (what it produces) of it:
Now the works of the flesh are manifest, which are these ; Adultery, fornication, uncleanness, lasciviousness, [20] Idolatry, witchcraft, hatred, variance, emulations, wrath, strife, seditions, heresies, [21] Envyings, murders, drunkenness, revellings, and such like: of the which I tell you before, as I have also told you in time past, that they which do such things shall not inherit the kingdom of God.
Galatians 5:19-21 KJV
Notice the works of the flesh are now manifest. Why? Because things that were in darkness are now made manifest/revealed by the true light of Christ:
For it is a shame even to speak of those things which are done of them in secret. [13] But all things that are reproved are made manifest by the light: for whatsoever doth make manifest is light.
Ephesians 5:12-13 KJV
The deeds of the flesh/grass is made manifest/revealed by the Light of Christ and destroyed by the burning heat generated by said Light, as written by James. Said another way, the light of the Spirit, which is the Light of the Risen Son, destroys the flesh and the works thereof:
For if ye live after the flesh, ye shall die: but if ye through the Spirit do mortify the deeds of the body, ye shall live.
Romans 8:13 KJV
The death of the flesh and the works of it is only accomplished when the heat of the sun of righteousness begins burning up the ungodly/earthy elements in our lives, allowing us to walk with God. For it’s only when we are walking in his Spirit will we not fulfill the lust of our flesh.
Heat of the day (the light of darkness)
As addressed before, the heat of day is biblically synonymous with death. Here, we will examine how “the heat of the day” concept applies to the devil.
Saying, These last have wrought but one hour, and thou hast made them equal unto us, which have borne the burden and heat of the day.
Matthew 20:12 KJV
In this parable, those who came in the last hour are representative of believers in Christ. We don’t bear the burden because of Christ:
Come unto me, all ye that labour and are heavy laden, and I will give you rest. [29] Take my yoke upon you, and learn of me; for I am meek and lowly in heart: and ye shall find rest unto your souls. [30] For my yoke is easy, and my burden is light.
Matthew 11:28-30 KJV
We don’t experience the heat of the day because he protects us from it:
Revelation 7:16 KJV They shall hunger no more, neither thirst any more; neither shall the sun light on them, nor any heat.
John 8:51 KJV Verily, verily, I say unto you, If a man keep my saying, he shall never see death.
Those who came first acknowledged that they bore the burden and heat of the day. This is because they lived in “the day” before the sun of righteousness rose, before Christ came and removed our burdens. These are old testament believers. They lived when the light of darkness (Satan) was blazing, when death reigned, when the vail stood between man and God. But God had promised them that protection from the heat of the sun (death) was coming:
And there shall be a tabernacle for a shadow in the daytime from the heat, and for a place of refuge, and for a covert from storm and from rain.
Isaiah 4:6 KJV
They shall not hunger nor thirst; neither shall the heat nor sun smite them: for he that hath mercy on them shall lead them, even by the springs of water shall he guide them.
Isaiah 49:10 KJV
That tabernacle/ the place of refuge, which protects us from the heat, is the LORD himself.
I will say of the LORD, He is my refuge and my fortress: my God; in him will I trust.
Psalm 91:2 KJV
The old testament believers bearing the burden and the heat of the day means that they died. They died in faith waiting for the fulfillment of the promise:
These all died in faith, not having received the promises, but having seen them afar off, and were persuaded of them, and embraced them, and confessed that they were strangers and pilgrims on the earth.
Hebrews 11:13 KJV
However, believers today will never die, because the promised shelter from the heat (death) waited for, we have received in Christ:
And whosoever liveth and believeth in me shall never die. Believest thou this?
John 11:26 KJV
The death of the old testament believers is not about them dying physically, but death as in separation from God. In the flesh, they were separate from God (as are we), but in the Spirit we are all connected to God. The coming of Christ, allowed them (and us) to walk in the Spirit and walking in the Spirit is walking in the light of God, whilst walking in the flesh is walking in the light of the devil:
But ye are not in the flesh, but in the Spirit, if so be that the Spirit of God dwell in you. Now if any man have not the Spirit of Christ, he is none of his.
Romans 8:9 KJV
For I am persuaded, that neither death, nor life, nor angels, nor principalities, nor powers, nor things present, nor things to come, [39] Nor height, nor depth, nor any other creature, shall be able to separate us from the love of God, which is in Christ Jesus our Lord.
Romans 8:38-39 KJV