Shared ground
Ephesians 1:15–16 presents the writer’s ongoing response to good reports about the recipients. He has “heard” about two visible marks of their life together: their faith “in the Lord Jesus” and their love “toward all the saints.” On the basis of this news (and tied to what he has just celebrated in 1:3–14), he describes a settled pattern: he keeps for them and keeps bringing them up in his prayers.
The text links belief and love: faith is oriented to Jesus as Lord, and love is directed broadly to God’s people. Thanksgiving and intercession are also linked: his prayer does not replace gratitude; it expresses it.
Where interpretation differs
Some readers think “for this cause” points mainly to the encouraging report he received (“because I heard…”). Others think it primarily points back to the preceding paragraph (1:3–14): because God has acted “in Christ,” his response is thanksgiving and prayer, with the report being the immediate occasion.
Some also hear “faith in the Lord Jesus” mainly as inward trust, while others think it includes loyalty/allegiance that shows up publicly. The wording can carry both ideas, and the surrounding emphasis on community life makes the public dimension hard to ignore.
Finally, “all the saints” is taken by some as all believers everywhere, and by others as all the believers connected to their community network (including groups they may not naturally favor). Either way, the stress falls on non-selective love.
Why the disagreement exists
The phrases are brief and can be read with different “reference points.” “For this cause” could look backward to 1:3–14 or forward to the report; “faith” can be heard as trust or allegiance depending on how one thinks early Christian communities used the word; and “all the saints” can be heard as universal or more local depending on how broadly one imagines the audience.
What this passage clearly contributes
These verses show that the writer treats faith in Jesus and love toward God’s people as reportable realities, not merely private feelings. They also show a model of pastoral concern at a distance: hearing about people’s faith and love leads not to flattery alone but to sustained gratitude directed to God and continued prayerful remembrance of them (preparing for the requests of 1:17–23, e.g., Ephesians 1:17).