Years after they took up the name "Jehovah's Witnesses", or in 1938, Rutherford decided that singing songs would be deleted, so that an "Introduction Statement" could be announced instead. Rutherford felt that singing songs often expressed things that were out of harmony with God's kingdom.
Watchtower/1938/May/1st/pg.139
"We are now in the time of great peril. Satan the Devil, the opposer of God and the enemy of man, has brought all the woe, sorrow and suffering upon the world, and the end of his organization and his wicked reign is now at hand. The great crisis has arrived because Jehovah, the Almighty God, has enthroned Christ Jesus, his King and Rightful Ruler of the world, and who will bring order out of confusion and will bestow blessings upon those who worship God in spirit and in truth. Soon he will destroy the wicked and will fully vindicate Jehovah's name. All the peoples of earth are now being separated by the Lord into two classes. Every person, therefore, must be in oneof such classes. Those on the Lord 's side, and who are obedient to him, are called 'sheep', while those who remain with the Devil and his organization are designated as 'goats'. Armageddon, which is near at hand, will witness the destruction of the 'goats'. The 'sheep', or obedient ones, will find protection and salvation in the Lord. All the obedient ones must be witnesses to the name and to the kingdom of Jehovah God, and in this witness work the anointed must take the lead, and all who love God and his kingdom must follow in the same way. God has commanded that just preceding Armageddon a world-wide witness must be given among the nations to the people of good will, that they may be warned of what is about to come to pass and that they may flee to the kingdom as the only place of safety. This assembly of God's people is here to study a portion of his Word that we may be better equipped to follow his instructions. Let everyone, including all the children, feel and appreciate the importance and solemnity of this occasion and of this study and be alert and diligent to gain as much information as possible, which will enable them to prove their integrity toward Jehovah and to serve his kingdom. What we learn here at the Lord's hand we should, at the appropriate time, go forth and make known to others, that the name of Jehovah may be declared and made known in the earth. Let all keep in mind that the Almighty God, the Creator of heaven and earth, has provided the kingdom, which is the sole hope of the peoples of earth, and that our greatest privilege is now to gain a knowledge, understanding and an appreciation of our relationship to God and his kingdom, and to make known his great name and his kingdom. To this end we will now pursue our study."