Will I turn to the people - This promise must refer to the conversion of the Jews under the Gospel.
That they may all call - That the whole nation may invoke God by Christ, and serve him with one consent; not one unbeliever being found among them.
The pure language, ברורה שפה saphah berurah, may here mean the form of religious worship. They had been before idolaters: now God promises to restore his pure worship among them. The word has certainly this meaning in Psalm 81:6; where, as God is the speaker, the words should not be rendered, "I heard a language which I understood not," but, "I heard a religious confession, which I approved not." See Isaiah 19:18; Hosea 14:3; and see Joel 2:28, where a similar promise is found.
For then - In the order of God‘s mercies. The deliverance from Babylon was the forerunner of that of the Gospel, which was its object. The spread of the Gospel then is spoken of in the connection of God‘s Providence and plan, and time is overlooked. Its blessings are spoken of, as “then” given when the earnest was given, and the people, from whom according to the flesh Christ was to be born, were placed anew in the land where He was to be born. Lap.: “The prophet springs, as is his wont, to Christ and the time of the new law.” And in Christ, the End of the Law, the prophet ends.
I will turn - Contrary to what they had before, “to the people,” literally, “peoples,” the nations of the earth, “a pure language,” literally, “a purified lip.” It is a real conversion, as was said of Saul at the beginning 1 Samuel 10:9; “God” (literally) “turned to him another heart.” Before the dispersion of Babel the world was “of one lip,” but that, impure, for it was in rebellion against God. Now it shall be again of “one lip;” and that, “purified.” The purity is of faith and of life, “that they way call upon the Name of the Lord,” not as heretofore on idols, but that every tongue should confess the one true God, Father Son and Holy Spirit, in Whose Name they are baptized. This is purity of faith. To “call upon the Name of the Lord Jesus” Acts 22:16; Romans 10:13 is the very title of Christian worship; “all that called upon the Name” of Jesus, the very title of Christians Acts 9:14, Acts 9:21; 1 Corinthians 1:2. “To serve Him with one consent,” literally, “with one shoulder,” evenly, steadfastly, “not unequally yoked,” but all with united strength, bearing Christ‘s “easy yoke” and “one another‘s burdens, fulfilling the law of Christ.” This is purity of life. The fruit of the lips is the “sacrifice of praise” Hebrews 13:15.
God gave back one pure language, when, on the Day of Pentecost, the Holy Spirit, the Author of purity, came down in fiery tongues upon the Apostles, teaching them and guiding them “into the whole truth” John 16:13, and to “speak to every one in his own tongue, wherein he was born, the wonderful works of God” Acts 2:8, Acts 2:11. Thenceforth there was to be a higher unity than that of outward language. For speech is not the outer sound, but the thoughts which it conveys and embodies. The inward thought is the soul of the words. The outward confusion of Babel was to hinder oneness in evil and a worse confusion. At Pentecost, the unity restored was oneness of soul and heart, wrought by One Spirit, whose gift is the one Faith and the one Hope of our calling, in the One Lord, in whom we are one, grafted into the one body, by our baptism Ephesians 4:3-6. The Church, then created, is the One Holy Universal Church diffused throughout all the world, everywhere with one rule of Faith, “the Faith once for all delivered unto the saints,” confessing one God, the Trinity in Unity, and serving Him in the one law of the Gospel with one consent.
Christians, as Christians, speak the same language of Faith, and from all quarters of the world, one language of praise goes up to the One God and Father of all.: “God divided the tongues at Babel, lest, understanding one another, they should form a destructive unity. Through proud men tongues were divided; through humble Apostles tongues were gathered in one. The spirit of pride dispersed tongues; the Holy Spirit gathered tongues in one. For when the Holy Spirit came upon the disciples, they spake with the tongues of all, were understood by all; the dispersed tongues were gathered into one. So then, if they are yet angry and Gentiles, it is better for them to have their tongues divided. If they wish for one tongue, let them come to the Church, for in diversity of the tongues of the flesh, there is one tongue in the Faith of the heart.” In whatever degree the oneness is impaired within the Church, while there is yet one faith of the creeds, He alone can restore it and ‹turn to her a purified language,‘ who first gave it to those who waited for Him. Both praise and service are perfected above, where the Blessed, with one loud voice, ‹shall cry, Salvation to our God which sitteth upon the Throne and unto the Lamb; blessing and glory and wisdom and thanksgiving and honor and power and might be unto our God forever and ever‘ Revelation 7:10, Revelation 7:12. And they who ‹have come out of great tribulation and have washed their robes and made them white in the Blood of the Lamb,” shall be ‹before the Throne of God and serve Him day and night in His Temple‘ Revelation 7:14-15.”