No one can have spiritual understanding of God without the sovereign hand of God sending the Holy Spirit to give understanding and knowledge concerning the truth of God. Having knowledge of God both salvifically and in sanctification is an act of God's grace! The knowledge of God can be distinguished into two categories: Salvific knowledge of Him via regeneration and increasing knowledge of Him throughout the sanctification process. A characteristic of a Christian is growing in the knowledge of God as this leads to sanctification which is the will of God for the elect. Theology matters! Disciple (mathétés) means learner, student. The problem in not seeing God is not an eye problem, but a heart problem. This is why only the hearts that have been regenerated by the supernatural sovereign monergistic power of God can have any spiritual understanding of God. Paul prays for God to give them increased knowledge/understanding of the hope of His effectual call. The elect of God have a hope (meaning a guarantee) of an inheritance in Christ. The true believer has eternal life, will forever dwell with God, and will see God as He is! The greater the knowledge we have of Him the more assured we are of our salvation and inheritance.