Thus says the LORD, the King of Yisra'el, and his Redeemer, the LORD of Hosts: I am the first, and I am the last; and besides me there is no God. - Yeshayahu/ Isaiah 44:6
Listen to me, O Ya`akov, and Yisra'el my called: I am he; I am the first, I also am the last. - Yeshayahu/ Isaiah 48:12
I am the Alef and the Tav, the First and the Last, the Beginning and the End. - HaHitgalut/ Revelation 22:13
What does it mean that HaShem is First and Last, the Beginning and the End? If Adonai is God then He is eternal, meaning He has no beginning and no end. If HaShem is the Creator of all things that means He is not contained within the things He created, but above those things. Time is a creation of HaShem so that means HaShem is not contained within time. Eternity means absence of time and if He's Eternal then time has no meaning to Him.
When God says He's the Beginning and the End, it doesn't mean that time began with Him and it will end with Him, because His person has nothing to do in essence with time, so this must be about something else.
The only way I can understand these words is that He is The First, Highest, Greatest, First in position not in age, He's above all things while at the same time He is the Last, the End, the lowest, the servant... the One that lowered Himself lower than anyone and anything to redeem those that were too low to reach Him.
It could be hard for some to wrap their minds around it, but it's the same as believing that God is both Son and Father, both Lion and Lamb, both Water and Fire, etc.
Being First didn't stop Him to be Last, and being Last didn't stop Him to be First.
No matter what your position is, it's not higher than being the First, so that means you can also humble yourself to be last, and no matter how low you are, He went lower than that, so that means you can't let your position as being ~the last~ to stop you from trying to better yourself. Either way there is hope, that's why Yeshua came on earth> to give us hope no matter if we are first or last.
Bat Melech בת מלך