Jeremiah 1

2 witnesses of Christ here.

Jehovah who foreordains prophets

Then the word of the LORD came unto me, saying, Jeremiah 1:4–5

Jehovah, the premortal Christ, reveals that He knew Jeremiah and ordained him before he was born. This matches the Restoration teaching that noble spirits were chosen in the premortal world.

AttestedJehovah — the LORDHe speaks in the first person

How we know: Jehovah is the premortal Christ (Abraham 1:16; D&C 110:3–4)

the same event in Abraham 3:22-23 — Abraham is shown he was chosen before he was born among the noble and great ones.
the same event in D&C 138:55-56 — Joseph F. Smith sees leaders who received their first lessons in the world of spirits and were prepared before birth.

The LORD touches the prophet's mouth

But the LORD said unto me, Say not, I am a child: for thou shalt go to all that I shall send thee, and whatsoever I command thee thou shalt speak. Jeremiah 1:7–9

The LORD personally reaches out, touches Jeremiah's mouth, and gives him His words, promising to be with him. The wording echoes the promise of the prophet like Moses into whose mouth God would put His words, a prophecy fulfilled in Christ.

AttestedJehovah — the LORDHe appears

How we know: the verse itself names Him

alludes to Deuteronomy 18:18 — I will raise them up a Prophet ... and will put my words in his mouth.
alludes to Isaiah 6:6-7 — Isaiah's call: a live coal touches his mouth.
the same title in Jeremiah 1:19 — The promise 'I am with thee, saith the LORD, to deliver thee' is repeated.