"Your Father is training you for a part the angels cannot sing, and His conservatory is the school of sorrows. Others have said that He sends sorrow to test you, yet this is not the case. He sends sorrow to educate you, thereby providing you with the proper training for His heavenly choir.
In the darkest night He is composing your song. In the valley He is tuning your voice. In the storm clouds He is deepening your range. In the rain showers He is sweetening your melody. In the cold He is giving your notes expression.
And as you pass at times from hope to fear, He is perfecting the message of your lyrics. O dear soul, do not despise your school of sorrow. It is bestowing on you a unique part in the heavenly song."
Rev 15:3 And they sing the song of Moses, the servant of God, and the song of the Lamb, saying, "Great and amazing are your deeds, O Lord God the Almighty! Just and true are your ways, O King of the nations!
Rev 14:3 and they were singing a new song before the throne and before the four living creatures and before the elders. No one could learn that song except the 144,000 who had been redeemed from the earth.