Quote from : True Christianity Book

The first help to prayer is our only Mediator and Advocate, Jesus Christ, the Son of God, 1 John 2:2. He is pleading our cause before God, when we are hardly able to express what we want; who is therefore called the Word of the Father, because God, by him, has discovered his will to us; as he is also called 'the Mediator,' because he solicits our cause before God. When Moses complained that he was of slow speech, and a slow tongue, that so he might avoid carrying the commanded message to Pharaoh, God tells him, 'Aaron thy brother can speak well, he shall be to thee instead of a mouth.' Se we also, when we shall pray, are dull, and slow of speech, and therefore must fly to Christ, our heavenly Aaron, who is to us instead of a mouth. Therefore Christ commands us to pray in his name, who is our eternal High-priest, 'having an everlasting priesthood,' (Heb. 7:24,) 'interceding for us,' (Rom. 8:34,) 'in whom we have boldness,' and access with confidence by the faith of him,' Eph. 3:12.