Certainly everyone enjoying his union with Christ where He is, has entered in spirit into the Father's house. The Father's house is the only resting place for the prodigal.
There are but two places -the "great way off," where he received the kiss of reconciliation, and the father's house; the first step from the one to the other is entrance into untold joy and blessedness. The right of entrance is not only assured but enjoyed. Sitting in the heavenlies in Christ is our calling, together with all saints. Entering into and enjoying the Father's house now in the Spirit is the right of children brought nigh unto Him.
The "holiest of all" is the moral character of the Father's house; Jesus is there for us. He has entered into heaven itself, there to appear in the presence of God for us. He is the great High Priest. He sustains us there, and He is there. The more you are in the holiest, where you worship, the more will your assurance of the Father's love deepen without requiring any evidence of it. The perfect rest of heart found in the perfect acceptance vouchsafed to you there, will promote and enlarge in your heart the knowledge of the Father's love. When the love of the Father is in you (see 1 John 2:1919They went out from us, but they were not of us; for if they had been of us, they would no doubt have continued with us: but they went out, that they might be made manifest that they were not all of us. (1 John 2:19)), you are sensibly enjoying that which could, and would, provide and procure anything for you, and the love of the world is not in you. It is not anything you see which detains or draws your heart, because it is already occupied with a love that has the command of everything, and is ready to use all for you.
The Lord sustains you in the unclouded light of His own presence, growing more and more into the pleasures that are at His right hand.