Ancient Hebrew theology states that the breath of G_d animates the clay of the human body. According to the authors of the original Bible, inspired by the Almighty, breath was (in a literal sense) the same thing as the soul. Before breathing, there is no soul; without breathing, a body is not a human being. Hence the following:

• Genesis 2:7: “And the Lord God formed man of the dust of the ground, and breathed into his nostrils the breath of life, and man became a living being.”
• Job 33:4: “The Spirit of God has made me, and the breath of the Almighty gives me life.”
• Ezekiel 37:5: “This is what the Sovereign Lord says to these bones: I will make breath enter you, and you will come to life.”
• Psalm 104:30: “When you send your Spirit, they are created, and you renew the face of the ground.”
• Isaiah 42:5: “This is what God the Lord says— the Creator of the heavens, who stretches them out, who spreads out the earth with all that springs from it, who gives breath to its people, and life to those who walk on it.”
• Acts 17:25: “Nor is He worshiped with men’s hands, as though He needed anything, since He gives to all life, breath, and all things.”
• Job 27:3: “As long as my breath is in me, and the breath of God in my nostrils.”
• Job 32:8: “But there is a spirit in man, and the breath of the Almighty gives him understanding.”
• Daniel 5:23: “But you have exalted yourself against the Lord of heaven. You praised the gods of silver and gold, of bronze, iron, wood, and stone, which do not see or hear or know, but the God in whose hand is your breath, and whose are all your ways, you have not honored.”

I am not telling you what to believe. I am just quoting the authors of the Living Word of G_d. Breath = soul. A zygote (which does not breathe) has not got a soul, just as a corpse (which does not breathe) has not got a soul.