Consider the verse 6. “The voice said, Cry. And he said, What shall I cry?”
Here we have the Spirit of Christ announcing the advent of God the Son. We see him as Angel of his presence operating in the Old Testament. He was present as ‘the spiritual Rock’ in the wilderness. St Paul asserts that it was Christ(1 Co.10:4). Here Isaiah asks the spirit ‘What shall I cry?”
So voice in the wilderness in the verse before(v.3) urging Prepare ye the way of the Lord’ belongs to that Spirit and it is voice doubling for the eternal Word. The Word was God and from the beginning he was with God (John1:1).
All scripture is given by inspiration of God (2 Ti.3:16) refers to the Word. It is the word of His grace that can build us up and also comfort us. The word ‘comfort’ used in the first two verses were directed to Jerusalem and also for His people everywhere. It is the rest that Jesus Christ offered.”Come unto me, all ye that labor and are heavy laden, and I will give you rest (Matt.11:28).”
In the verse quoted from epistle to Timothy we read that the scripture is ‘profitable for doctrine’ and wherewith can anyone who is heavy laden be comforted? It is only possible by learning of our Savior Lord. He is holding the other end of the yoke which is light and easy, His doctrine is that of reconciliation. We who were dead in sins and burdened by demands of the flesh were given a new lease of life. He reconciled us to God the Father.
the metaphor of grass for flesh is appropriate. Our physical bodies and transient glory that goes with it are blown away. Instead it is the indwelling Spirit that helps us run Christian Living.”For my yoke is easy, and my burden is light (Matt.11:30)” Therefore we shall rely on the word of God to keep our faith life ever lively. “The grass withereth, the flower fadeth: but the word of our God shall stand for ever” Ps.119:89. This is our constitution and we believe it as true.”And the glory of the Lord shall be revealed, and all flesh shall see it together: for the mouth of the Lord hath spoken it(v.5). So help me, God.
Comfort ye, comfort ye my people, saith your God.
2 Speak ye comfortably to Jerusalem, and cry unto her, that her warfare is accomplished, that her iniquity is pardoned: for she hath received of the Lord’s hand double for all her sins.
3 The voice of him that crieth in the wilderness, Prepare ye the way of the Lord, make straight in the desert a highway for our God.
4 Every valley shall be exalted, and every mountain and hill shall be made low: and the crooked shall be made straight, and the rough places plain:
5 And the glory of the Lord shall be revealed, and all flesh shall see it together: for the mouth of the Lord hath spoken it.
6 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.
8 The grass withereth, the flower fadeth: but the word of our God shall stand for ever.
9 O Zion, that bringest good tidings, get thee up into the high mountain; O Jerusalem, that bringest good tidings, lift up thy voice with strength; lift it up, be not afraid; say unto the cities of Judah, Behold your God!