Deuteronomy 18:18
16 This accords with what happened at Horeb in the day of the assembly. You asked the Lord your God: “Please do not make us hear the voice of the Lord our God anymore or see this great fire anymore lest we die.” 17 The Lord then said to me, “What they have said is good. 18 I will raise up a prophet like you for them from among their fellow Israelites. I will put my words in his mouth and he will speak to them whatever I command. 19 I will personally hold responsible anyone who then pays no attention to the words that prophet speaks in my name. 20 “But if any prophet presumes to speak anything in my name that I have not authorized him to speak, or speaks in the name of other gods, that prophet must die.
John 12:49
47 If anyone hears my words and does not obey them, I do not judge him. For I have not come to judge the world, but to save the world. 48 The one who rejects me and does not accept my words has a judge; the word I have spoken will judge him at the last day. 49 For I have not spoken from my own authority, but the Father himself who sent me has commanded me what I should say and what I should speak. 50 And I know that his commandment is eternal life. Thus the things I say, I say just as the Father has told me.”
Notes and References
"... There is also concurrence and correspondence in three of these passages in John. Jesus’ words in 8:26, 28, 12:49–50, and 17:8 are all recorded in contexts where there are clearer allusions to the same book or passage. Moreover, the criterion of correspondence - when more parallels occur in the same context, it increases the probability of an allusion - is found in those three passages as well. As I have noted elsewhere, there are other allusions in those passages so the proposed allusions to Isaiah 49 and 50 in these passages add to the other parallels which are present and increase the likelihood that allusions to the Servant passages are intended. Based on the criterion of uniqueness, there are close affinities between the theme of Jesus speaking the words of the Father with Deuteronomy 18:18 and the prophet-like Moses that is predicted to arise. In fact, there are verbal parallels between Deuteronomy 18:18 and John. Deuteronomy 18:18 contains τὸ ῥῆμά as does John 3:34 and 17:8. Deuteronomy 18:18 states how the prophet will speak the words of God (λαλήσει αὐτοῖς), which is similar to Jesus’ claims that he speaks (λαλεῖ) the words of God (3:34; 8:26, 28; 12:49) ..."
Day, Adam W. Jesus, the Isaianic Servant: Quotations and Allusions in the Gospel of John (p. 175) Gorgias Press, 2018