Isaiah 56:6-7 (HCSB)

And the foreigners who join themselves to the Lord
minister to Him, love the name of Yahweh
and become His servants,
all who keep the Sabbath without desecrating it
and who hold firmly to My covenant —
 I will bring them to My holy mountain
and let them rejoice in My house of prayer.
Their burnt offerings and sacrifices
will be acceptable on My altar,
for My house will be called a house of prayer
for all nations.”

     Jesus will quote from vs. 57 when he throws out the money-changers from the temple, demonstrating his command of the Scriptures which he must have memorized.  Did he need to memorize them?  Hmm…
     Huge promise here for those who are not Jews, and we see it literally fulfilled in John 4, when the people of Sychar come to faith in Jesus the Messiah.  They are accepted and really the beginning of the fulfillment of God’s house being a house of prayer for all the nations.  
     Of course today we see it fulfilled even more widely as people from all nation-states are believers and the church universal focuses in on spreading the gospel to every ethnic group in earth.  All may come to God’s house in Jesus.