During their seventy years of captivity in Babylon, the people of Israel didn’t feel much like singing:
“By the rivers of Babylon, there we sat down, yea, we wept, when we remembered Zion. We hanged our harps upon the willows in the midst thereof. For there they that carried us away captive required of us a song; and they that wasted us required of us mirth, saying, Sing us one of the songs of Zion. How shall we sing the Lord’s song in a strange land?” (Psa. 137:1-4).
We are told that the children of Israel were well known for their music, and we wouldn’t be surprised if this were so, for faith in our God has inspired countless great compositions down through the centuries. But when their captors demanded that they sing the songs that expressed the joy they felt in their God and their homeland, the sorrow they felt in their hearts would not allow these captives to give voice to such expressions while shackled with the chains of Babylonian bondage.
But if God’s people cannot sing outside of their Promised Land, how can Paul call on us to be “speaking to yourselves in psalms and hymns and spiritual songs, singing and making melody in your heart to the Lord” (Eph. 5:19)? How can we sing the Lord’s songs in the land made strange to us by the anti-God sentiment found all around us, and the iniquity upon iniquity that we see on every hand?
We believe it is because God has already “raised us up together, and made us sit together in heavenly places in Christ Jesus” (Eph. 2:6). Remember, we serve a God that “calleth those things which be not as though they were” (Rom. 4:17). In that passage, God was able to call Abraham “the father of many” before he had any children. This is because God had promised to multiply his seed, and so in the mind of God he already had a multitude of descendants! In the same way, God can use the past tense in describing how we are already “glorified” (Rom. 8:30), and since the Lord has promised that we will one day “reign with Him” (II Tim. 2:12) from thrones on which we will sit together with Christ in heavenly places, in His mind it is as good as done, we are as good as there.
And if that’s not something worth singing about, I don’t know what is! source