R. Plaut:
This haftarah is the first of seven that are called sheva de-nechamta, "the seven [haftarot] of consolation." Six others will follow, all from the Second Isaiah, the last one to be recited on the Shabbat before Rosh Hashanah.
As most modern scholars see it, chapter 40 opens the prophecies of the Second Isaiah. This unknown preacher-poet lived among the exiles in Babyon (6th century B.C.E.), and at some later time his writings were attached to those of the First Isaiah, who lived well over a century earlier
Connection of haftarah and Shabbat:
The weekly portion is read on the Shabbat after Tisha B'Av. . . The haftarah begins with words of comfort: the term of Israel's exile is over, for God not only desires to liberate them but can and will do so.
The setting:
Undoubtedly there were many among the exiles who doubted that God could redeem them, the promises of the prophets notwithstanding. But with Cyrus about to conquer Babylon, and (so the Prophet hoped) willing to let the exiles return to their native land, Isaiah preaches that God wills surely proceed to make good on the divine promise.
The message:
The haftarah may be divided into three parts:
1. A brief general introduction setting out Isaiah's theme: he has been charged by God to deliver a message of hope. (43:1-2)
2. God's might is unbounded, and this power will now be demonstrated in the redemption of Israel. (40:1-20)
3. Conclusion. God's might is such that Israel's oppressors will crumble, "bringing princes to naught, making earth's rulers as nothing." (40:21-26)
(The Haftarah Commentary, p. 439)

God too needs comforting
The first three words of the haftarah (Nachamu Nachamu ammi, Comfort, O comfort My people), gave rise to several wordplays:

Instead of ammi, My people, a midrash reads immi, with Me - hence, "Comfort, O comfort [Jerusalem] together with Me," says God.
Rabbi Berachia the Priest read the words "Comfort My people " as "Comfort Me, comfort Me, O My people." [Reading nachamuni ami instead of Nachamu ami].
- Midrash
(The Haftarah Commentary,​​​​​​​ p. 459)

R. Plaut:
Why has God forsaken us?
The cry for divine help - whether comic from the heart of an individual or of a collective - is as old as the religious quest itself. And since such prayers are sometimes answered and sometimes not, the question "Why not?" is likely to shake the very foundations of faith. It is found in the Bible, as it is in other scriptures . . .
It is (the) anguish of Israel that Isaiah expresses also in the beginning of next week's haftarah [see above]. . .
It wa the cry of Job and the pleading of the victims of persecution, from ancient times to the Holocaust and beyond. The failure to receive a clear answer has turned many a believer into an unbeliever. The bridge from "Why doesn't God help?" to "God cannot help" and "There is no God" is all too easily crossed.

Yet in the end there is no answer that will stand the proof of the scientist. Faith is strengthened or weakened by the experiences we have, but whether we believe in a God who can save us is far removed from the actual existence of the Divine. One is a personal attitude, the other a reality that does not depend on how we feel about it.
There is also an intermediate position, which is that of doubt: "We'd like to believe, but are not sure how we can." This is the situation that the Second Isaiah faced in this opening chapter of his book. He reassures his people that God desires not only to save Israel, but is also capable of doing it. The Eternal is not merely a divine friend with goodwill, but a power beyond all powers who can rescue the beleaguered nation.
Withal, Isaiah does not pretend to know why the rescue has been so long delayed. For ultimately a believer knows that there are limits to human understanding. We are not God, and our human mind operates on a level different from the Divine.
The border of human understanding is the door to faith. We cannot know God's plans, but we can trust God as our friend. All true relationships are ultimately based on such trust.
(The Haftarah Commentary, pp. 446-447)

R. Sheryl Nosan-Blank:
She has been standing, alone, on a high mountaintop, for a very long time. Before her, she can see Jerusalem, but it is cloaked in a dark, dense fog. In the distance, through the mist, she can just make out more remote villages and towns of Judah. Generations have heard her comforting message, a healing balm for their wounded souls; but the same generations have refused to see her, intentionally or unintentionally denying her womanly strength, spiritual insight, and. wisdom. Commentators, translators, and grammarians have attempted to veil and vanquish her, but, throughout, she has remained a steadfast and faithful woman. Who is this solitary woman, unfailingly providing her strong, gentle message of comfort and hope?
We meet the messenger in Haftarat Ve'etchanan, which is read on Shabbat Nachamu. Shabbat Nachamu . . . God's instructions for comforting (personifies) Jerusalem as an anguished woman . . . In response, voices call out, on God's behalf, in versed 3-8. These Divine voices, which Rashi defines as emanating from ruach ha-kodesh, the Holy Spirit," or Ha Kodesh Baruch Hu, the "Holy, Blessed God," are ultimately not the voices that comfort Zion. Rather than relying solely on Divine but disembodied voices of police, God turns to a messenger of flesh and blood . . . the m'vaseret (female messenger of good tidings) . . .
It is not surprising that God calls on a female messenger to console woeful-woman Jerusalem. In Hebrew grammar, cities are always female and, in the Bible, Jerusalem is frequently referred to as a woman . . . Stereotypically, women communicate easily and compassionately with other women. Thus, the female messenger - m'vaseret - is the voice the female Jerusalem can hear clearly. It is surprising, then, that the female form for the word for messenger occurs nowhere in the entire Bible except here, in Isiah 40:9. Even more surprising is the consistent, unabashed attempts to hide her as a woman for centuries, while heeding her as a messenger. . .
The difficulty commentators face is the radical shift to the image of a strong, solitary woman, able to discern and carry the word of God to bring comfort to those in need.
The m'vaseret's gift to us is comfort, with a caveat. She has long urged us to be consoled, but as a woman of insight and observation, she sees through the barriers (we) build, which may keep us from finding solace. . . The messenger realises that we value our strength and independence, but tells us that if our hearts and souls are open to being comforted, we may be able to hear God call us, and support us, even as "God calls all [the stars] by name . . . and not one is lost" (Isa. 40:26). She tells us that if we are receptive, the Holy One will embrace, nurture, and guide us. . .
The m'vaseret is a partner with God, following the mitzvah of the Compassionate One, to bring comfort. God's message shapes her words, God's direction guides her feet, and perhaps God's help is delivered through her hands. As God comforts Rachel, weeping for her children (Jer. 31:15-19), and as Ruth comforts Naomi, bitter from her losses (Ruth 1:16-17), so does the m'vaseret comfort woeful-woman Jerusalem; so too can we comfort those who weep, live in bitterness, or are overcome with woe. When we do so, we too become God's messengers. We can join the newly redeemed and finally visible m'vaseret, so that she no longer stands, solitary on the mountain, and we ourselves can become messengers of God's comfort.
(The Women's Haftarah Commentary, pp216-220)