This is what YHWH God says in the Jewish Bible, the Old Testament Book of Isaiah:
"Who has performed and done this, calling the generations from the beginning? I, Yahweh, am the first, and with the last — I AM.” Isaiah 41:4
"This is what the Lord, the King of Israel and its Redeemer, the Lord of Hosts, says: I am the first and I am the last. There is no God but Me." Isaiah 44:6
“Listen to Me, Jacob, and Israel, the one called by Me: I AM; I am the first, I am also the last." Isaiah 48:12
And this is what God says in the Book of Revelation:
“... It is done! I am the Alpha and the Omega, the Beginning and the End. I will give water as a gift to the thirsty from the spring of life. The victor will inherit these things, and I will be his God, and he will be My son." Revelation 21:6-7
In the following chapter, Jesus said,
"I am the Alpha and the Omega, the First and the Last, the Beginning and the End." Revelation 22:13
Previously, Jesus had said,
“I assure you: Before Abraham was, I AM.” John 8:58
“Don’t be afraid! I am the First and the Last, and the Living One. I was dead, but look—I am alive forever and ever, and I hold the keys of death and Hades." Revelation 1:17-18
Now let's try to make this as easy as possible for Muslims to comprehend:
"I, Yahweh, I Am, I am the first and I am the last. There is no God but Me. I am the Alpha and the Omega, the Beginning and the End."
And Jesus says:
"I AM. I am the Alpha and the Omega, the First and the Last, the Beginning and the End."
Earlier, Jesus had also said, "The Father and I are one." John 10:30
Do you get it yet?