He was telling the Samaritan of the prophecy given by Isaiah 56:7.
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.
He’s talking about the B’nai Noach.
Really? Because it sure sounds like a future gathering. As I understand B'nai Noach, you essentially believe in the family of man (all who are descended from Noah after the flood). Yet, we have that brotherhood simply by birth. What is missing is the Spirit of God. The real fulfillment of the prophecy you cited is Christ bringing home the Family of God in the New Covenant.