"For this reason I too, having heard of the faith in the Lord Jesus which exists among you, and your love for all the saints, do not cease giving thanks for you, making mention of you in my prayers" (Eph. 1:15-16).
Your love for other Christians is as much a mark of true faith as your love for God.
The Ephesian Christians demonstrated two important characteristics of genuine Christian faith: faith in the Lord Jesus and love for fellow believers.
"Faith in the Lord Jesus" implies both an affirmation of Christ's deity and submission to His sovereignty. Because He is God, He is the Sovereign Lord, so we must obey what He commands (John 14:15; 1 John 2:3-6).
Your "love for all the saints" is as much a mark of true faith as your love for God. John said, "The one who says he is in the light and yet hates his brother is in the darkness until now" (1 John 2:9). In that passage "light" is a metaphor for righteousness and truth, and "darkness" is a metaphor for sin and error. It is sinful and erroneous to claim you love God if you have no love for other believers. Those who love God will love fellow believers as well.
If you love others, you will pray for them and praise God for their spiritual progress—as Paul did for the Ephesians—and they will do the same for you. That's a wonderful dynamic within the Body of Christ, and one that you must diligently pursue.
Suggestions for Prayer
Read Philippians 1:9-11 and Colossians 1:9-14.