Hebrews 3:6

But Christ as a Son over his own house
As Moses was not, though the Jews say that he was (tybd hyram) ^F1 and (tybh leb) {b}, "lord and master of the house"; yea, and (tyb Nb) , "the Son of the house" ^F3; but this he was not: Christ is the Son and heir, the Lord and master; he is a Son, not by creation, or by adoption, or by office, but by nature: hence it appears that he is God, and is equal with God; and this his sonship is the foundation of his office, and he becomes the heir of all things: and when he is said to be "as a Son", it does not intend mere resemblance; but is expressive of his right to heirship and government, and of the esteem and reverence he had in his house, and of his fidelity as a Son there; and though he was a servant, as man and Mediator, and had a great piece of service to perform, and which he has performed with diligence and faithfulness, yet he was also a Son, Lord and heir, as Moses was not; and he is over the house of God, as King, priest, and prophet in it, and as the firstborn, Son and heir, and as the master and governor of it; and which is called his own, because given him by the Father, purchased by himself, and which he has built, and in which he dwells:

whose house are we;
believers in Christ, whether Jews or Gentiles; who, as lively stones, are built up a spiritual house, in whom Christ dwells by faith, and over whom he presides and reigns:

if we hold fast the confidence and the rejoicing of the hope firm
unto the end.
These words are not to be understood as a condition of the former assertion; nor is a final falling away from grace to be inferred from hence, for the supposition proves not such an inference, but the contrary; namely, that they that have true faith, hope, and confidence, shall keep them to the end; and therefore are the house of Christ: besides, the doctrine of apostasy is quite repugnant to the apostle's argument; according to which, Christ might have no house, and can have none till men have persevered: but the apostle's design is to give a word of exhortation to himself and others, to hold fast the confidence; and so the words are rather descriptive of the persons, who are the house of Christ; such who have a good hope, through grace, wrought in them, and can rejoice in hope of the glory of God; and can use freedom of speech and boldness at the throne of grace; and have an holy confidence of interest in the love of God, and salvation by Christ, and go on in the exercise of these graces to the end of their days.