One of the fundamental beliefs of Judaism is that life does not begin with birth, nor does it end with death. This is articulated in the verse in Kohelet (Ecclesiastes 12:7), “And the dust returns to the earth as it was, and the spirit returns to G‑d, who gave it.”
In Jewish understanding it means the dust of the body existed before birth, and the spirit that exists within you does not 'perish' but changes location. We were, we are, we will be.
A basic law of physics known as the first law of thermodynamics is that no energy is ever “lost” or destroyed; it only assumes another form. If such is the case with physical energy, how much more so a spiritual entity such as the soul, whose existence is not limited by time, space, or any of the other delineators of the physical state. Certainly, the spiritual energy that in the human being is the source of sight and hearing, emotion and intellect, will and consciousness does not cease to exist merely because the physical body has ceased to function; rather, it passes from one form of existence (physical life as expressed and acted via the body) to a higher, exclusively spiritual form of existence.
"Olam Ha Ba" literally means "the world to come" in Hebrew. Early rabbinic texts describe Olam Ha Ba as a physical realm that will exist at the end-of-days after the Messiah has come and God has judged both the living and the dead. The righteous dead will be resurrected to enjoy a second life in
Olam Ha Ba
.
Our Jewish rabbi taught us that there is a 'world to come'
after our lives here;
Matthew 12:32
And whoever speaks a word against the Ben HaAdam [Moshiach] will be granted selicha (forgiveness), but whoever speaks against the Ruach Hakodesh, selicha will not be granted him either in the Olam Hazeh or in the Olam Habah.
As did his tzadikim;
John 3:12
If I told you about things of the Olam Hazeh and you have no emunah, how will you have emunah if I tell you about the things of the Olam Haba?
John 3:17
For Hashem did not send the Ben HaElohim into the Olam Hazeh that he might judge the Olam Hazeh, but that the Olam Hazeh might be brought to the Geulah (Redemption) of the Olam Haba through him (Rebbe, Melech HaMoshiach). [YESHAYAH 53:11]
Luke 16:9
And I say to you, use the mammon (the wealth of the Olam HaZeh) to make for yourselves yedidim (friends, chaverim), so that when unrighteous mammon fails, they may welcome you into the mishkenot olam (eternal dwellings of the Olam HaBah).
The geulah is the resurrection of the dead, at Moshiach's return. The only Jewish sect that was vehemently opposed to this were the Tzadokim (Sadducees), the Prushim (Pharisees) fully believed in the resurrection of the dead, and an afterlife. The only issue 'some' of the pharisees had was they did not believe Yeshua was the Moshiach. Otherwise they too believed in living eternally in the world to come.
So, when we die our bodies return to the dust of the earth, ashes to ashes. And our spirit returns to Hashem. Both still exist. (Kohelet 12:7) Awaiting the coming redemption (geulah) where we are resurrected and restored to life eternal.
When Moshiach returns and restores all things our bodies will be resurrected to live eternally in the Olam Haba. (above verses)