How does the doctrine of total depravity explain the need for regeneration?

The doctrine of total depravity, stemming from mankind's fall in Adam, teaches that every person is born in spiritual death and depravity, as shown in Ephesians 2:1-3. This condition means that, left to ourselves, we lack the capacity to understand or embrace the gospel. Regeneration, or the new birth, is vital because only through the sovereign act of the Holy Spirit can we be quickened from our dead state to believe in Christ. Thus, regeneration is necessary for anyone to respond to God's call effectively and embrace salvation.