This is how I respond.
It depends upon what kind of Spirit he/she comes at you with. One can feel if someone truly wants an answer because they are confused, or if they are trying to trap you with nonsense for argument sake. Why quibble with
Luke 18:19 when there are so many other scriptures that confirm that Christ was God manifested in the flesh? I would give him/her those scripture. Here's just few for appetizers.
I and my Father are one.
(
John 10:30)
1 In the beginning was the Word, and the Word was with God, and the Word was God.
2 The same was in the beginning with God.
3 All things were made by him; and without him was not any thing made that was made.
10 He was in the world, and the world was made by him, and the world knew him not.
14 And the Word was made flesh, and dwelt among us, (and we beheld his glory, the glory as of the only begotten of the Father,) full of grace and truth.
(
John 1:1-3, 10,14)
Therefore the Jews sought the more to kill him, because he not only had broken the sabbath, but said also that God was his Father, making himself equal with God.
(
John 5:18)
Jesus saith unto him, Have I been so long time with you, and yet hast thou not known me, Philip? he that hath seen me hath seen the Father; and how sayest thou then, Shew us the Father?
(
John 14:9)
Believest thou not that I am in the Father, and the Father in me? the words that I speak unto you I speak not of myself: but the Father that dwelleth in me, he doeth the works.
(
John 14:10)
And
without controversy great is the mystery of godliness: God was manifest in the flesh, justified in the Spirit, seen of angels, preached unto the Gentiles, believed on in the world, received up into glory.
(
I Timothy 3:16)
6 Who, being in the form of God, thought it not robbery to be equal with God:
7 But made himself of no reputation, and took upon him the form of a servant, and was made in the likeness of men:
8 And being found in fashion as a man, he humbled himself, and became obedient unto death, even the death of the cross.
(
Phillippians 2:6-8)