"All this is said (Jn 16:26-27) to Christians for the purpose of giving them the boldness and confidence to rely on this Man and to pray with complete assurance; for we hear that in this way He unites us with Himself, really puts us on a par with Him, and merges our praying into His and His into ours. Christians can glory in this great distinction. For if our prayers are included in His, then He says: "I will tell of your name to my brothers" (Ps 22:22) and "The Spirit himself bears witness with our spirit that we are children of God, and if children, then heirs-heirs of God and fellow heirs with Christ' (Rm 8:16-17). What greater honor could be paid us than this, that our faith in Christ entitles us to be called His brethren and coheirs, that our prayer is to be like His, that there is really no difference except that our prayers must originate in Him and be spoken in His name if they are to be acceptable and if He is to bestow this inheritance and glory on us. Aside from this, He makes us equal to Himself in all things; His and our prayer must be one, just as His body is ours and His members are ours. So St. Paul says: 'We are members of His body' (Eph 5:30), of His flesh and bone.

 

To give them greater comfort, Christ must remind His disciples of this glory in these last words of His; but He must do so by telling them that everything hinges on their belief that He was sent for this purpose in accordance with God's counsel and will, in order that they may pray confidently in His name and do everything Christians should do. For this dare not be omitted or forgotten. Otherwise they would pray and worship no differently from the way the Turks and the heathen do.

 

Martin Luther, Sermons on John's Gospel, 16.26-27