Paul is talking to the church in Ephesus about the unified body and how God aims for it to grow up into the image of Christ.
When Paul says, “speaking the truth in love, we are to grow up in all aspects into Him who is the head, even Christ“, it is God’s plan that mind and spirit, body and soul, thinking and heart all must be involved in the growth of the church.
When a man is overcome with emotion but he hasn’t got the truth, it goes nowhere. When another man speaks the truth but he is cold and heartless, it will miss the mark. The God of truth is the God of love. For the church to fully represent Him, we must be doggedly Scriptural and we must always show the lovingkindness of God. The truth must be spoken with love. Both are essential to do God’s work.