Priesthood is the divine provision of grace to sustain those who have been set in God's righteousness before Him in Christ. It reconciles the condition of a poor feeble creature on earth, liable to fall at any moment, with the glorious position which is his in Christ. I believe that Hebrews is the complement of the Epistle to the Romans—the one setting us, through redemption, before God in Christ, the other maintaining us there. In its prime aspect it is preventive and sustaining. "Hold Thou me up, and I shall be safe." You find at the end of Heb. 4, the provisions made in order that we may not fall in the wilderness—the detective power of the Word of God to deal with the will, and the supporting priesthood of Christ to sustain us in our weakness. So we are to go boldly to the "throne of grace" and find timely help to sustain, that we may not fail.
Then there is advocacy for absolute falls. "If any man sin, we have an advocate." 1 John 2:11My little children, these things write I unto you, that ye sin not. And if any man sin, we have an advocate with the Father, Jesus Christ the righteous: (1 John 2:1). He is engaged before and with the Father for us, and the result of His advocacy is to turn the Word, by the Spirit, in its convicting power, on the conscience: and then, when confession is produced, the soul having bowed under His action, restoration follows. A double action takes place—conviction for the failure, and, on confession, restored communion.
In Numb. 18 you have priestly service in grace to maintain communion. In chapter 19, the provision, not of maintaining communion by priestly grace, but for the restoration of communion individually when lost—the double application of the ashes and water on the third and seventh days answering to that of advocacy—the third day showing what sin is in respect of grace—the seventh showing what grace is in respect of sin. The ashes and water used here point, the first to the impossibility of the sin being imputed, as the victim on whom they were was wholly burnt—the latter to the Word of God in its convicting and restoring power by the Holy Ghost. This answers now to the thought of advocacy.
I do not like the word, One-who-manages-your-affairs—it is too long. Solicitor, though good, is not suitable, from its associations in common use—(Advocate is the same word in Greek as Comforter, in John 14) but One who manages your affairs is the thought.