The Power of the Gospel
9 After this I looked, and behold, a great multitude that no one could number, from every nation, from all tribes and peoples and languages, standing before the throne and before the Lamb, clothed in white robes, with palm branches in their hands, 10 and crying out with a loud voice, "Salvation belongs to our God who sits on the throne, and to the Lamb!" 11 And all the angels were standing around the throne and around the elders and the four living creatures, and they fell on their faces before the throne and worshiped God, 12 saying, "Amen! Blessing and glory and wisdom and thanksgiving and honor and power and might be to our God forever and ever! Amen." - Revelation 7:9-12
The gospel is enough
“If there shall be in heaven a multitude surpassing all human arithmetic, out of all nations, and kindreds, and peoples, and tongues, how certain the Gospel is to achieve yet a great success.” - C.H. Spurgeon.
“We can be sure that the gospel of God will not fail to save all the people of God. The Lord has his people, and they will certainly trust in Christ. The centuries-spanning, worldwide church fulfills the promise made to Abraham of innumerable descendants. Finally, the success of the gospel reveals the gospel’s power. John wrote in a day of persecution, when the church had no political power or any cultural advantage. All it had was the gospel, and the sight of innumerable believers shows that the gospel is enough. It will accomplish God’s ends even when preached by the powerless.” (Tabletalk)