This is the second thing that Paul prays that the Ephesians will be able to do; the first is that they "understand." Alternate translation: "and to know how great Christ's love for us is"
This is the third item for which Paul bends his knees and prays ([Ephesians 3:14](../03/14.md)). The first is that they would "be strengthened" ([Ephesians 3:16](../03/16.md)), and the second is that they "can understand" ([Ephesians 3:18](../03/18.md)).