Paul is concerned that some believers will not develop as they should. He suggests a remedy – speaking the truth in love.
Speaking the truth in love requires not holding back what the truth is. It means that we cannot be selective. Speaking the truth in love takes account of the needs of the other person. It means that we have to be sensitive. Speaking the truth in love requires ensuring the other person understands the truth. The truth should not be stated in an obscure way, otherwise there will not be any growth. Therefore we have to be simple and clear. Profound truths can be stated simply and elementary truths can be present obscurely.
Speaking the truth in love means that we do not use scripture truths in order to get our own way. It means we all speak the truth with the good of others in mind. We spread the gospel because we want people to be saved. We repeat divine promises because we desire people to be comforted. We mention other promises because we want wanderers to return to the fold. We give warnings because we do not want them to fall.
The obvious demand of this requirement is that there must be fellowship between Christians when they will lovingly speak truth to one another (Mal. 3:16).
The outworking will be growth. Paul says that the church develops when the believers live and speak the truth out of love. I would mention three details of his illustration.
First, doing this gives us deeper appreciation of our union with Christ: we ‘grow up in every way into him who is the Head’. This means that we get to know Jesus progressively and draw out of his resources increasingly, which is unity in action. For growth to be consistent, there has to be an ongoing right relationship with Jesus.
Second, doing this enables the church to function. Each Christian is likened to a joint in a body, with each joint fitly framed together. Some joints are bigger than others, but each joint receives life from the Head in order to function appropriately. Paul uses a word that means abundant supply. What is being supplied is grace by the Holy Spirit, but it is grace given through the words and lives of fellow believers.
Third, when each Christian does what he or she should do (when each part is working properly), a community of love is the result, which is unity in action. Not only must there be a right relationship with Jesus, there must be a similar relationship with his people.