Because the Lord is at hand, “the peace of God, which surpasses all knowledge, guards [our] hearts and [our] minds.” We have no cause for anxiety.
Paul reminds us to “think about” excellence and to “practice” what is worthy of praise as well. If we think about “whatever is true, whatever is honorable, whatever is just, whatever is pure, whatever is commendable” and then practice these things, then “the God of peace is with [us].” (Philippians 4: 8 – 9)
And, as a result, we have no fear. Our Lord is at hand. Therefore, says Paul, “rejoice in the Lord always; again I say, Rejoice.” (Philippians 4: 4)