Is the Jehovah of the Old Testament the same as Christ in the New Testament?

Yes, the Jehovah of the Old Testament is Christ in the New Testament. The context states the Lord in the Old Testament is Jehovah, and Jehovah in the New is Christ, as shown in John's Gospel where Jesus said, 'Before Abraham was, I AM,' identifying Himself as the Old Testament I AM, Jehovah.

Les explains that the Lord in the Old Testament is Jehovah, and the Jehovah of the New Testament is Christ. He points to John's Gospel where Jesus said, 'Before Abraham was, I AM,' and asks who the I AM of the Old Testament is—Jehovah. Therefore, the prophecy that Jehovah the Christ shall be King over all the earth is sure, and Christ will return and stand on the Mount of Olives.

Is Jesus Christ of the New Testament the same as Jehovah of the Old Testament?

Yes. The New Testament's Jesus Christ is the Jehovah of the Old Testament and the God of Genesis 1—one and the same God. The only difference is that He manifested Himself in flesh. Saul's encounter confirms this: when he asked who Jehovah was, Jehovah answered, I am Jesus.