Isaiah 56:1-2 These are the words of the Lord; Maintain justice and do what is right, for My deliverance is close at hand and My victory will soon be revealed. Happy is the person who follows these precepts and holds fast to them, who keeps the Sabbaths unprofained and his hand from all wrongdoing.
Isaiah 56:3-5 The foreigner who has given his allegiance to the Lord must not say; The Lord will exclude me from His people. The eunuch must not say: I am naught but a barren tree. The eunuch’s who keep My Sabbaths and choose to do My will, holding fast to the covenant, will receive from Me something better than children – a memorial and a name within My Temple. I shall give them everlasting renown.
Isaiah 56:6-7 So too, with the foreigners who give their allegiance to Me, to minister to Me and love My name and become My servants. All who keep My Sabbaths holy and hold fast to My covenant; these I shall bring to My holy Mountain and give them joy in My House of prayer. Their offerings and sacrifices will be acceptable on My altar, for My House will be called a House of prayer for all nations.
Isaiah 56:8 This is the word of the Lord, who gathers those driven out of Israel;
I shall add to those who have already been gathered. John 10:16
This Bible passage, written by the prophet Isaiah, gives a wonderful promise to every person – regardless of race, colour or gender. The promise of the Lord, to give them;
“Joy in My House of prayer”
In verse 8, it shows that this will happen after all the faithful Christians, [the real Israelites of God] have gathered into the Land. Ezekiel 20:34-35, Jeremiah 30:10 They will be divided into 12 groups, into the 12 ‘tribes’ of Israel.
Also as in verse 7, the Temple will be built by them.
Isaiah 66:18-21…I am coming to gather peoples of every tongue. They will come to see My glory. I shall put a sign on them and will send them to preach the Gospel to all the peoples that have not heard of Me. The 144,000 Revelation 7:3-8 & 14:1-7
From every nation and by every means, My righteous people will come to My Holy mountain, Jerusalem, just as in ancient days, the Israelites brought their offerings to Me. Some of them, I shall take to be priests and Temple Levites. Revelation 5:9-10, 1 Peter 2:5
Some of these; are the 144,000 as mentioned in Revelation. This all must occur before the Return of Jesus. 2 Thess. 1:10…He reveals His glory among His own… Revelation 14:1
Reference: REB some verses abridged.