As promised, we're now skipping ahead to so-called Trito-Isaiah, chapters 56-66. It's entirely unclear why this material was tacked on to the earlier two books, as it is completely unrelated both in context and meaning. These chapters were written by anonymous people -- yes, probably several of them -- during the Persian period of the Judean restoration, i.e. about 520 - 400 BCE.
Since there's obviously no longer any need to prophecy the restoration of Judah, this material appears to concern theological and political disputes of the time. Note that the early period of the restoration is described in two versions, in the book of Ezrah/Nehemiah, but we don't know exactly when any of this was written and whether it corresponds with that period.
Anyway, Ch. 56 is interesting because it asserts that eunuchs can fully participate in religious life, which is a direct contradiction to Leviticus 21 and Deuteronomy 23. Specifically, the latter says "He that is wounded in the stones, or hath his privy member cut off, shall not enter into the congregation of the LORD." The declaration in Leviticus is just as clear and absolute. Clearly the absolute decrees of the Torah were by now open to dissent. Also, like the Book of Ruth, this chapter allows for converts from other nations to join the congregation -- again a direct contradiction to the Torah but a feature of modern Judaism.
56 This is what the Lord says:
“Maintain justice
and do what is right,
for my salvation is close at hand
and my righteousness will soon be revealed.
2 Blessed is the one who does this—
the person who holds it fast,
who keeps the Sabbath without desecrating it,
and keeps their hands from doing any evil.”
3 Let no foreigner who is bound to the Lord say,
“The Lord will surely exclude me from his people.”
And let no eunuch complain,
“I am only a dry tree.”
4 For this is what the Lord says:
“To the eunuchs who keep my Sabbaths,
who choose what pleases me
and hold fast to my covenant—
5 to them I will give within my temple and its walls
a memorial and a name
better than sons and daughters;
I will give them an everlasting name
that will endure forever.
6 And foreigners who bind themselves to the Lord
to minister to him,
to love the name of the Lord,
and to be his servants,
all who keep the Sabbath without desecrating it
and who hold fast to my covenant—
7 these I will bring to my holy mountain
and give them joy in my house of prayer.
Their burnt offerings and sacrifices
will be accepted on my altar;
for my house will be called
a house of prayer for all nations.”
8 The Sovereign Lord declares—
he who gathers the exiles of Israel:
“I will gather still others to them
besides those already gathered.”
God’s Accusation Against the Wicked
9 Come, all you beasts of the field,
come and devour, all you beasts of the forest!
10 Israel’s watchmen are blind,
they all lack knowledge;
they are all mute dogs,
they cannot bark;
they lie around and dream,
they love to sleep.
11 They are dogs with mighty appetites;
they never have enough.
They are shepherds who lack understanding;
they all turn to their own way,
they seek their own gain.
12 “Come,” each one cries, “let me get wine!
Let us drink our fill of beer!
And tomorrow will be like today,
or even far better.”