This word "partake" hearkens back to the tree in Lehi's and Nephi's dream. (Lehi's version is found in 1 Nephi 8.) People prefer to go join in a crowd inside a building. The building is a symbol of man's work. The "arm of flesh" is used to build such structures. No matter how "great" or "spacious" such work may be (1 Ne. 8: 31), it is nonetheless the product of human labor. In the dream, those who enter into the building do so to join the multitude in mocking and scorn of those who choose the tree instead. (1 Ne. 8: 33.) In contrast to this, the tree bearing fruit is a product of nature--God's product. Man's labors do not produce trees. Without God, trees do not exist. Man cannot take credit for either the tree or its fruit. It is a gift given to him.
Now the gift must be obtained by coming to the tree. You cannot partake of its fruit while standing at a distance. You must go to the tree, take the fruit in your hand, and "partake of the goodness of God" before you are able to realize how "delicious" this goodness truly is. (1 Ne. 8: 10-12.)
So Nephi's invitation to "partake of the goodness of God" is a reminder at the end of his record of the visions he received at the beginning of the record. Come, partake, be saved.
What would you need to do in order to "respect the words of the Jews, and also [Nephi's] words?" Why does he add "and the words which shall proceed forth out of the mouth of the Lamb of God?" Does this mean that if you have "respect" for Nephi's words and the Bible, you will receive other words? Words from "the mouth of the Lamb of God?" Does it suggest you will speak directly with Christ? That part of the fullness of this process is to once again speak to and hear from "the Lamb of God?" Will it result in Christ speaking to you in the flesh? (2 Nephi 32: 6.)
Why will Nephi's words "condemn you at the last day?" Why does Nephi bid an "everlasting farewell" to those who won't "partake of the goodness of God?"
Is Nephi uncharitable? Are his words harsh, unkind or intemperate? Should he be praising us more and condemning us less? Is this a "hard thing" he has spoken to us? (1 Nephi 16: 2.) If it is not harsh, unkind, or intemperate, then should this kind of warning be given by anyone who is concerned for the salvation of your soul? Why? If your messengers don't challenge you to repent, but instead use smooth words, reassuring you in your present course, would their message conflict with Nephi's message? What would you make of such a conflict between their praise and reassurance, and Nephi's stark warnings?