"And the glory of the telestial is one, even as the glory of the stars is one; for as one star differs from another star in glory, even so differs one from another in glory in the telestial world; For these are they who are of Paul, and of Apollos, and of Cephas. These are they who say they are some of one and some of another--some of Christ and some of John, and some of Moses, and some of Elias, and some of Esaias, and some of Isaiah, and some of Enoch; But received not the gospel, neither the testimony of Jesus, neither the prophets, neither the everlasting covenant." (D&C 76:98-101)
"All those named (Paul, Apollos, Cephas, Christ, John, Moses, Ellas, Esaias, Isaiah and Enoch) were true messengers or authorized prophets of God. In the list is the Son of God Himself. These claims are not being made by those who were following Buddha, Mohammed, Confucius, Zarathustra, Vishnu or Krishna. They are being made by Saints, who thought themselves justified because of their belief in authorized messengers sent from God." (Denver Snuffer)
Receiving the testimony of Jesus is more than believing in Jesus. "Eternal life", Jesus said was to "know God", and knowing God is more than knowing about him. Receiving the testimony of Joseph Smith, without going on do that which Joseph taught, that is having our own face-to-face visitation, which is a fulness of the Gospel, wherein we receive the actual Everlasting Covenant, and not just it's symbolic version which we receive in the temple.