According to this publication published by none other than those who want to gain followers of THEMSELVES, Christ assigned the preaching work to THEMSELVES and NOT Jehovah's Witnesses.
*** w07 4/1 pp. 24-25 Loyal to Christ and His Faithful Slave ***
Giving Loyal Support
14 The humble submission of the other sheep to the anointed members of spiritual Israel was foretold in the prophecy of Isaiah: “This is what Jehovah has said: ‘The unpaid laborers of Egypt and the merchants of Ethiopia and the Sabeans, tall men, will themselves come over even to you, and yours they will become. Behind you they will walk; in fetters they will come over, and to you they will bow down. To you they will pray, saying, “Indeed God is in union with you, and there is no one else; there is no other God.”’” (Isaiah 45:14) Symbolically, the other sheep today walk behind the anointed slave class and its Governing Body, following their leadership. As “unpaid laborers,” the other sheep willingly expend their physical strength and their resources in support of the worldwide preaching work that Christ assigned to his anointed followers on earth.—Acts 1:8; Revelation 12:17.