Let us learn a very practical lesson from this. We all have friends who are not Christians, about whom we are concerned. We are anxious to help them, and we talk to them about these things. We quote Scriptures to them and explain them. We try to show them the Christian attitude and position with respect to present conditions and the whole of life. But I must emphasize that if we leave it at that, it may come to nothing. You cannot reason anyone into the Christian life. You can give the reasons for believing but you cannot reason them into belief. You can put the case before them, but you cannot prove it as if it were a matter of a theorem in geometry. We must realize that while we are instructing them, we must also be praying for them. It is only as the Holy Spirit deals with them and prepares them and opens their understanding that they can receive the truth.
The Apostle is perfectly consistent with his own doctrine. He knew that it was as essential that he should pray for these Ephesians as that he should instruct them by his Epistle. We, likewise, must never forget that instruction and prayer go together. If you are interested in a particular person, and desire his salvation, you must not stop at befriending him, helping him, spending time with him, and putting the truth before him; equally you must pray for him. Indeed I would go so far as to say that unless you are giving more weight to your prayer than to your instruction your work is likely to be a failure.
Note the place that is given to intercessory prayer in the New Testament. It is extraordinary and quite amazing, and is exemplified particularly in the Apostle Paul. Notice, too, how very dependent Paul was upon the prayers of other Christians. In most of his letters he pleads with them to pray for him. He urges them to pray that he may have a door of opportunity, that he may have liberty, and so on. He fully realized his dependence upon the prayers of others."
—Martyn Lloyd-Jones (1972). The Unsearchable Riches of Christ: An Exposition of Ephesians 3 (pp. 110–111). Grand Rapids: Baker Book House.