P. communicated to me the question in your letter. John 13 is advocacy: that is not access, which is the point in Hebrews, but cleansing, and restoration to communion, as in 1 John 2-the intercession of the blessed Lord when we are actually defiled, when, being washed (bathed), we have defiled our feet.
In Hebrews we are perfected forever by the offering, and have boldness to enter into the holiest. Here it is a "part with me," and the present enjoyment of that is interrupted. The priesthood is for mercy and grace to help in time of need. We are feeble, have infirmities in the Hebrews, having to say to God: the word judges, the priesthood helps with grace in our position with God. In 1 John 1 we have fellowship with the Father and with His Son Jesus Christ our Lord.
John 14-16 refers to other subjects: what Christ was on earth as to His Person so that His coming again should have its value, what the Spirit would be to them, what He was in relationship to them in contrast with Israel, what the Holy Ghost would be revealing the glory, and then His presence on earth. Chapter 17 is neither priestly nor advocacy, in the sense of Hebrews and 1 John 2 It is essentially putting the disciples in His own place with the Father, and doing and looking to the Father to do when He was gone, all that was necessary for their being, and being maintained, in this place. It is not priesthood with God for mercy and help for feeble man, perfect in conscience with God, but feeble as man here; not failure calling for advocacy and cleansing as 1 John 2 and John 13 It is the Son looking to the Father to keep in, and fit for, His place on earth, those whom He had put there (vers. 1-8) when He had gone on high glorified. Only the three last verses add a heavenly character to their joy: the rest is their place here, even in glory: this is the Father's house. But Jesus is Son here, not properly Priest or Advocate. Only the Son, while God, and one with the Father, never from chapter 1:14 gets out of His place as Man in John, but receives all as such. I can only give the suggestions of the great leading principles. You must study the passages with that help which alone can make us understand the word, and is never refused to those who, not in searching merely but in all things, seek His face. He gives to all men liberally and upbraids not.
Very truly yours in the Lord.
September 11Th, 1870.