Heb 3:1
3:1 Wherefore, {1} holy brethren, partakers of the heavenly
    calling, consider the {a} Apostle and High Priest of our {b}
    profession, Christ Jesus;

 (1) Having laid the foundation that is to say, declared and
     proved both the natures of one Christ, he gives him three
     offices, that is, the office of a Prophet, King and Priest,
     and concerning the office of teaching, and governing,
     compares him with Moses and Joshua from Heb 3:1-4:14,
     and with Aaron concerning the priesthood. He proposes that
     which he intends to speak of, with a grave exhortation,
     that all our faith may be directed towards Christ, as the
     only everlasting teacher, governor, and High Priest.
    (a) The ambassador or messenger, as in Ro 15:8 he is
        called the minister of circumcision.
    (b) Of the doctrine of the gospel which we profess.

Heb 3:2
3:2 {2} Who was faithful to him that {c} appointed him, {3} as
    also Moses [was faithful] in all his house.

 (2) He confirms his exhortation with two reasons, first of all
     because Christ Jesus was appointed as such by God:
     secondly, because he thoroughly executed the offices that
     his Father commanded him.
    (c) Apostle and High Priest.
 (3) Now he comes to the comparison with Moses, and he makes
     them like one another other in this, that they were both
     appointed rulers over God's house, and executed faithfully
     their office: but he later shows that there is great
     dissimilarity in the same comparison.

Heb 3:3
3:3 {4} For this [man] was counted worthy of more glory than
    Moses, inasmuch as he who hath builded the house hath more
    honour than the house.

 (4) The first comparison: The builder of the house is better
     than the house itself, therefore Christ is better than
     Moses.  The reason for the conclusion is this: because the
     builder of the house is God, which cannot be attributed to
     Moses; and therefore Moses was not the builder, but a part
     of the house: but Christ as Lord and God, made the house.

Heb 3:5
3:5 And {5} Moses verily [was] faithful in all his house, as a
    servant, for a testimony of those things which were to be
    spoken after;

 (5) Another comparison: Moses was a faithful servant in this
     house, that is, in the Church, serving the Lord that was to
     come, but Christ rules and governs his house as Lord.

Heb 3:6
3:6 But Christ as a son over his own house; {6} whose {d} house
    are we, if we hold fast the {e} confidence and the rejoicing
    of the hope firm unto the end.

 (6) He applies the former doctrine to his purpose, exhorting
     all men by the words of David to hear the Son speak, and to
     give full credit to his words, seeing that otherwise they
     cannot enter into that eternal rest.
    (d) That is, Christ's.
    (e) He calls confidence the excellent effect of faith (by
        which we cry Abba, that is, Father), and to confidence
        he adds hope.

Heb 3:7
3:7 Wherefore (as the Holy Ghost saith, To day if ye {f} will
    hear his voice,

    (f) So that God was to speak once again after Moses.

Heb 3:8
3:8 Harden not your hearts, as in the {g} provocation, in the
    day of temptation in the wilderness:

    (g) In the day that they troubled the Lord, or struggled
        with him.

Heb 3:10
3:10 Wherefore I was grieved with that generation, and said,
     They do alway {h} err in [their] heart; and they have not
     known my ways.

     (h) They are brutish and angry.

Heb 3:12
3:12 {7} Take heed, brethren, lest there be in any of you an
     evil heart of unbelief, in departing from the living God.

 (7) Now consider in the words of David, he shows first by this
     word "today"  that we must not ignore the opportunity while
     we have it: for that word is not to be limited to David's
     time, but it encompasses all the time in which God calls
     us.

Heb 3:13
3:13 But exhort one another daily, {i} while it is called To
     day; lest any of you be hardened through the deceitfulness
     of sin.

     (i) While today lasts, that is to say, so long as the
         gospel is offered to us.

Heb 3:14
3:14 {8} For we are made partakers of Christ, if we hold the {k}
     beginning of our confidence stedfast unto the end;

 (8) Now he considers these words, "If you hear his voice"
     showing that they are spoken and meant of the hearing of
     faith, opposite which he places hardening through unbelief.
     (k) That beginning of trust and confidence: in the speech
         of the Hebrews, he calls "beginning" that which is
         chiefest.

Heb 3:15
3:15 {l} While it is said, To day if ye will hear his voice,
     harden not your hearts, as in the provocation.

     (l) So long as this voice sounds out.