How do we know Christians are born of God?

In Psalm 87, verse 5 states that 'this and that man was born in her,' referring to Zion, depicting that citizens of this city are born again. This reflects the necessity of spiritual regeneration, as seen in John 3:3, where Jesus teaches the need for being 'born again' to enter the kingdom of God. This spiritual birth is initiated by God's grace through the Holy Spirit, who brings believers to life in Christ, making them new creations. It underscores the profound truth that salvation is a divine act where God gives life to those who were formerly dead in sins.