For this reason also, since the day we heard of it, we have not ceased to pray for you and to ask that you may be filled with the knowledge of His will in all spiritual wisdom and understanding, so that you will walk in a manner worthy of the Lord, to please Him in all respects, bearing fruit in every good work and increasing in the knowledge of God; strengthened with all power, according to His glorious might, for the attaining of all steadfastness and patience; joyously giving thanks to the Father, who has qualified us to share in the inheritance of the saints in Light.
Pray for your friends like this!
Paul knew that the Colossians would not be able to live this way on their own strength. So he prayed that God would strengthen them with His strength, so that their spiritual growth would last a long time.
He prayed for joy in their hearts as they thanked God for His grace in their lives. We sometimes think that the important things to focus on in life are "steadfastness and patience", which Paul prays for, but that experiencing joy is optional and just if you're lucky. But Paul is concerned that the Colossians experience joy in their relationship with God.
To God it is perfectly legitimate to pray for His joy in people's lives. Pray that they're filled to overflowing.