Why is the Son of God also called a ‘Man of sorrows’?
When the Son of God appeared in Flesh and lived among men, He stood apart from them in ways men have yet to fathom.  For, outwardly He appeared like any other ‘man’ and also attired Himself just like every other ‘common man’.  That is right!  Not like their kings and rulers, nor their priests and rabbis, not even like their outlaws. 
What is more?  He lived and moved among the commonest of them. 
Yet, He stood apart from every single one of them.  So that, multitudes flocked around Him and followed Him –  to hear Him and to be delivered of their troubles.  For, that were just what He was doing.  So much so that it disturbed the rulers and authorities, and they in turn followed Him albeit for different reasons altogether! 
“Just as there were many who were appalled at Him – His appearance was so disfigured beyond that of any man and His form marred beyond human likeness. ” (Isa 52:14).
 “…… He had no beauty or majesty to attract us to Him, nothing in His appearance that we should desire Him.  He was despised and rejected by men, a ‘Man of sorrows’, and familiar with suffering.  Like one from whom men hide their faces, He was despised, and we esteemed Him not.”  (Isa 53:2-3).  
WHY? : 
BECAUSE HE BORE THE SORROWS OF THIS WORLD – our sufferings, our sicknesses, our afflictions of this world, even our iniquities, our curses and death.  
He bore them as He moved among the masses, just as it is testified in Isa 53:2-3.   And He bore them TO THE cross, just as it is testified in Isa 52:14.  The sorrow that marred and disfigured His countenance on the cross, though briefly, was total and to its completion.  Thus in Him it was fulfilled once and for all.  And none need look elsewhere!
FOR HE BORE OUR SORROWS UNLIKE ANY MAN EVER DID OR CAN HOPE TO EVER DO.  Oh, and He definitely did not bear them like those who love to sit in Moses’ seat (Matt 23:4) and lord it over!
Everywhere He went (and He covered all the regions of Israel and Judea, even Samaria), He was visibly moved by compassion for the masses.  Looking at them, He grieved that they were like sheep without their Shepherd.  He wept with the grief-stricken.  And He was aggrieved that in spite of all God’s attempts to reach out to them and lift them from their miry pits, their spirits were in constant strife with the Spirit of God.  And now that He was amidst them, actually making the fullness of Him visible to them, they believed Him not.   So He wept for the disaster that they were willfully inviting upon themselves.  He mourned for the prophesied loss of their children.  He wept over their desolation!  (Matt 9:36, Matt 26:38, Mat 27:46, Lk 19:41-44, Gen 6:6, Lk 23:28-39, Jn 11:35, Eph 4:30 etc.)
He was not known to laugh nor smile, nor while away His time in frivolity and leisure.  He never uttered a careless word. 
Every single Word He spoke demonstrated the Power and Authority of God over the world, so that people realized they were unlike any they were accustomed to hearing.  And true to His Word, they experienced His deliverance in every manner, unlike ever witnessed before by any man.
Yes, we must understand that He who is the Creator is also the Redeemer and the Judge.   And we cannot even come close to understanding the Son of God as ‘Man of sorrows’ if we fail to fathom why the Spirit of God grieves in the first place (Eph 4:30).   
From the time it was first revealed (Gen 6:6) until the climaxing magnitude of it which will bring even Heaven TO A COMPLETE STANDSTILL FOR HALF AN HOUR (Rev 8:1), it is the Spiritual sorrow of God benighted to man, except to the discerning few (Lk 19:41-42). 
I hope and pray that you are one among the few as in it lies your hope.  To that end, it is imperative that I now reveal why He bore our sorrows.   And the answer is simply this – He bore them so that we may be delivered of each one of them.  That is, (for eg., refer Isa 61:1-3): 
  •  Instead of the curses, we may be blessed;
  • Instead of the heavy burden and hard labor, we may be yoked with His light and easy yoke;
  • Instead of sicknesses and afflictions, we may be healed;
  • Instead of sorrow and weeping, we may be filled with lasting Joy and surpassing Peace;
  • Instead of death, we may enjoy His Life – the abundant and eternal life of God;
  • Instead of the marred and fading beauty we inherit from our earthly fathers, we may be transformed into the   radiant glory of His holy likeness – our ‘lost’ likeness of the holy God, our Heavenly Father.  
  • Instead of dying the slow death as testimonial tombs of mankind, we may live the victorious life as temples of the Living God;
  • Instead of a body that remains susceptible to sickness and death as it is to sin and its woes, we may receive the Heavenly body of perfect holiness and perfect freedom from all bondages;
  • Last but not the least, instead of eternal condemnation, we may partake of His eternal Salvation.
[Note: Obviously we can only experience the FULLNESS of all above after the redemption of our bodies into the holy and heavenly bodies.  Nevertheless, the good news is that He allows us to sample them in abundant measures in our earthly bodies so that we are guaranteed of His infallible promises.  (eg. Eph 1:13-14)]
We who are likewise trained to grieve in the Spirit (Matt 5:4, Ezek 9:4, Jer 9:20 etc.) soon find ourselves  aggrieved that in spite of all the blessings made known to them, men continue to reject Him.  Even though He was pierced for our transgressions, He was crushed for our iniquities and He carried our infirmities, they lift their fists to His face and accuse Him that He does not care!
What is most appalling?  Even though He is the BLESSING our souls seek, they call Him ‘ACCURSED’!  Oh, yes, even that!  Read Isa 53:4-12, “Surely He took up our infirmities and carried our sorrows, yet we considered Him stricken by God, smitten by Him, and afflicted.……….”  
They did it then and THEY DO IT EVEN NOW.  Read Gal 3:13.  While at it, also read Deut 21:22-23, the referential text on which it is based.  Read the two verses and ask yourselves, how the two can even remotely refer to the ‘Blessed One’?
How can He, IN WHOM THERE IS NO SIN, become a curse, a byword?  Yet men call Him just that.  The Jews and the Gentiles alike, as Gal 3:13 will testify.  For in so doing, DO THEY NOT SEEK TO JUSTIFY THE CRUCIFYING OF HIM? 
Because, first of all, the original text (Deut 21:22-23) as mentioned earlier DOES NOT IN ANY WAY allude to Jesus or His death.  How blind these guides are is prima facie evidenced by the fact that they clearly see no difference between ‘NAILED TO THE CROSS’ and ‘HANGED ON A TREE’!   Just as they do not between the Innocent and the guilty and between holy God and mortal man!
The Truth is that Deut 21:22-23 prophesies about Judas, the son of perdition, who is the accursed of God and a devil (eg. Jn 6:70-71) – PROVING HIMSELF FOR WHO HE IS BY HANGING HIMSELF TO DEATH ON A TREE (Matt 27:5).  
Just as Zech 11:13 also prophesies of his treachery, where the Lord reveals that He will be valued at thirty pieces of silver.
Though king Saul’s death may also be deemed as an indirect act of suicide, it is Judas Iscariot who sets the precedence in exposing the devil in man by his suicide.  INDEED IT DOES NOT COME AS ANY SURPRISE TO LEARN THAT THE EVIL ACT OF SUICIDE IS SERPENT’S INHERENT OPTION!  
We must understand that God’s holiness is that which cannot be tainted or tarnished.   This is why though men ridicule Him and speak ill of Him, though they blaspheme His holy Name and testify falsely against Him, He remains UNTAINTED AND UNTARNISHED.  (This is the reason why they seem to get away with it for now,  or at least until at last they would have filled up the measure of their sins and their own words will condemn them!) 
And this is precisely the reason why only He was eligible to bear our sins, our sufferings, our sicknesses, our death and our curses.  Only His holiness could triumph over them all and come unscathed.  He is the only One to have overcome the world just as He is the only One to have overcome death (Jn 16:33b). 
And so He proved to all and sundry, when even though for a brief moment it had seemed to appear that the Father had rejected Him on the cross (Matt 27:46), the very next moment He was witnessed committing His Spirit to the Father (Lk 23:46). 
And a Roman centurion who was a witness to it testifies, “Surely this man was the Son of God!” (Mk 15:39). 
“.. All nations will be blessed through Him, and they will call Him ‘BLESSED.”  (Ps 72:17)
What spirit of man can understand the overwhelming sorrow of the Lord, weighed down by which He was seen to bleed from His forehead in the garden of Gethsemane, on the eve of His crucifixion?  What spirit of
man can fathom the sorrow which transfigures itself into the cleansing Blood – the Blood that He shed even before He was laid on the cross?  And what spirit of man can claim the credit for His vicarious sacrifice when He was already pouring Himself out like a drink offering for us?  What spirit of man can understand the sorrow of the Son as He momentarily also shouldered the sorrow of the Father who had to momentarily reject His people so that He may Himself work out their salvation for them in order that they may be united to Him forever? 
To those whose eyes will open and whose spirits will understand, it has also been revealed that He will pour out on them the Spirit of Grace and Supplication.  And they will look on Him, the One they have pierced, and they will mourn for Him as one mourns for an only child, and grieve bitterly for Him as one grieves for a firstborn son.  The weeping among His people will be indeed great on the day of their revelation (eg. Zech 12:10). 
And it will be fulfilled unto them, just as He has promised in His time of mounting distress, “For I tell you, you will not see Me again until you say, ‘BLESSED IS HE WHO COMES IN THE NAME OF THE LORD.’” (Matt 23:39) 
Oh!  Blessed are You O Lord Who comes in the Name of the Lord!  Come Lord Jesus!  Come!