Paul thanks God for the believers’ faith in Jesus and their love for others. He continually prays that God would give them wisdom and deeper understanding, so they may clearly see:
-> the hope they have in Christ,
-> the richness of the inheritance God has prepared for His people,
-> and the greatness of God’s power working in those who believe.

In short: Paul is praying that believers grow in spiritual insight, hope, and awareness of God’s mighty power at work in their lives.