These two verses are evidently a quotation from 2. But they are not a literal repetition of the words of the prophet. When we quote the inspired word of God, we must repeat it literally; otherwise we cannot be certain that we are saying what the Spirit intended to say. But the Divine Author, or Inspirer, of the Scriptures does not come under that rule. His word is always the truth.
Some commentators hold that the Prophet Isaiah, in these verses, on behalf of the Lord, invites the gentile nations to come and join Israel in the establishment of the Millennial Kingdom of God, (see vv. 6-8) where water, wine, milk, bread, etc.; that is, abundant prosperity, will be had without money and without price. Probably, there is some truth in that; for, undoubtedly, social and economic conditions will, during the Millennium, be different from what they now are. For one thing, there will probably be no interest-bearing debt, and to that extent the prosperity promised will not cost anything. It will be had "without money and without price." But that does not say that there will be no money as a medium of exchange. When Jacob reads this passage of Isaiah, he means not only temporal prosperity, but above all, spiritual abundance; for he explains: "Feast upon that which perisheth not, neither can be corrupted, and let your soul delight in fatness." (v. 51)
Jesus had this passage in mind, possibly, when he stood on the Temple ground one day and said with a loud voice: "If any man thirst, let him come unto me and drink." (John 7:39)