In this book, unless otherwise stated, the words "us" and "we" refer to Paul and the believers in Ephesus, as well as all believers. (See: [[rc://en/ta/man/translate/figs-exclusive]])
This can be stated in an active form. Alternate translation: "Let us praise the God and Father of our Lord Jesus Christ" (See: [[rc://en/ta/man/translate/figs-activepassive]])
Possible meanings 1) the phrase "in Christ" refers to what Christ has done. Alternate translation: "through Christ" or "through what Christ has done" or 2) "in Christ" is a metaphor referring to our close relationship with Christ. Alternate translation: "by uniting us with Christ" or "because we are united with Christ" (See: [[rc://en/ta/man/translate/figs-metaphor]])