Apart from physical death, Scripture speaks of a second type of death. This is known as spiritual death.

Spiritual  Death

Spiritual death is when a person is alive physically, but dead spiritually. All of us are born spiritually dead, separated from  God. The Lord  said to Adam.

But you must not eat from the tree of the knowledge of good and evil, for when you eat of it you will surely die (Genesis 2:17).

Adam and Eve died spiritually at the time that they sinned -  they became different beings then the ones God had originally created They also began to die physically.

Separated By Nature

Humanity is now separated from God by nature. Jesus said.

Very truly, I tell you, anyone who hears My word and believes Him who sent Me has eternal life, and does not come under judgment, but has passed from death to life (John 5:24).

Were Dead

Not only is humanity separated from God by nature, humans are also hostile to Him. The Apostle Paul spoke of believers in the following way.

And you He made alive, who were dead in trespasses and sins in which you once lived, following the course of this world, following the ruler of the power of the air, the spirit that is now at work among those who are disobedient. All of us once lived among them in the passions of our flesh, following the desires of flesh and senses, and we were by nature children of wrath, like everyone else (Ephesians 2:1-3).

These believers had been spiritually dead in their trespasses and sin.

Died Spiritually

Paul wrote about being spiritually dead.

Once I was alive apart from law; but when the commandment came, sin sprang to life and I died (Romans 7:9).

Spiritually Dead

The wayward son was said to have been spiritually dead.

But we had to celebrate and be glad, because this brother of yours was dead and is alive again; he was lost and is found (Luke 15:32).

Result Of Sin

The reason we are all born spiritually dead has to do with sin. We receive our fallen nature from our parents. After Adam and Eve sinned, the death sentence was pronounced. All other humans have been born with their sinful nature (the exception to this was the Lord Jesus who was born without sin). Therefore each of us comes into the world spiritually separated from God.

Summary

All of us are born spiritually dead, or separated from God. This is because all of us have inherited the sin nature from Adam and Eve.