The Ignatius Catholic Study Bible New Testament (254 page)

3:5-6
Moses and Jesus are compared. • The backdrop is Num 12:7, where Moses is honored as the Lord's "servant", who is put in charge of his "house", i.e., the whole covenant people. Jesus is also a father figure over the household of God's people, not as a servant, however, but as the faithful first-born Son (1:4-6). Some perceive an additional allusion to Nathan's oracle, where the messianic heir of David is designated the "son" of God and the one who will "build" a "house" for God (2 Sam 7:13-14; 1 Chron 17:13-14). 
Back to text.

3:7-11
A citation from Ps 95:7-11. • The Psalmist reflects on the apostasy of the Exodus generation. The Hebrew version of Ps 95 focuses on the defiance of Israel at Massah and Meribah (Ex 17:1-7), but the Greek version quoted here laments the rebellion at Kadesh, where the Israelites, paralyzed by fear of the Canaanites, refused to seize possession of the Promised Land (Num 14:1-38). For this, the Lord swore an oath of disinheritance that condemned that entire generation (except Joshua and Caleb) to die in the wilderness without setting foot in Canaan. The readers of Hebrews face the same critical decision: like the Exodus generation, they too have experienced the salvation of God and now stand on the threshold of a heavenly inheritance; only by a faith in God that overcomes fear will they enter the eternal rest that awaits them. 
Back to text.

3:14 firm to the end:
The Letter to the Hebrews is adamant that even true believers can forfeit their salvation by forsaking the Lord (6:4-8; 10:26-31; 12:14-17). This warning applies to genuine Christian "brethren", who can "fall away" from God if they allow their hearts to become "evil" and "unbelieving" (3:12). 
Back to text.

3:15 Today, when you hear:
The author, alluding to Psalm 95 (quoted in 3:7-11), identifies the
voice
of God with the gospel message spoken through his Son (1:2; 2:3; 4:2) (CCC 1165). 
Back to text.

3:19 because of unbelief:
The Exodus generation refused to believe that God could give them a land occupied by fearsome Canaanite warriors (Num 13:25-33).
See note on Heb 3:7-11
. 
Back to text.

4:1-11
A theological explanation of
rest,
a term held in common by Ps 95:11 (3:11; 4:3-4) and Gen 2:2 (4:4). • The interpretation of these passages is typological, i.e., the land of Canaan in the psalm and the Sabbath day in Genesis are interpreted as spatial and temporal representations of heaven. Life itself is like a wilderness journey toward a better land and like a week of labor that leads to a day of refreshment. Readers are urged to persevere in faith lest they fail to enter the rest prepared for them by God (4:11) (CCC 624, 1720). • There are three rests of which he speaks: the first is the Sabbath, in which God rested from his works; the second is Palestine, in which the Jews found rest from their hardships; and the third is rest indeed—the kingdom of heaven— in which those who obtain it rest from their labors and troubles (St. John Chrysostom,
Homilies on Hebrews
6). 
Back to text.

4:1 the promise . . . remains:
The opportunity to take hold of salvation remains "today" but will soon pass by (3:13; cf. 2 Cor 6:2). 
Back to text.

4:4 God rested:
A citation from Gen 2:2. • God rested on the seventh day after creating the world in six days. The point is not that God was tired and needed a break; rather, he was showing us
our
need to live and work for the rest that lies ahead. The call to enter his rest is a call to unite ourselves with God—weekly on the Sabbath (Ex 20:8-11) and ultimately in the attainment of salvation (Rev 14:13) (CCC 345). 
Back to text.

4:7-8
The author demonstrates that the land of Canaan was only an earthly sign of a heavenly country (11:16). • His logic is historical: had
Joshua
given Israel the fullness of rest promised by God (Josh 1:10-13),
David
would not have reissued the invitation to enter God's rest long after the tribes had settled down in the land (Ps 95:7-11). 
Back to text.

4:12 the word of God:
Penetrates into the hidden recesses of the heart. If God finds the heart hard and unbelieving (3:8, 10, 12, 15), his word becomes a weapon that destroys. If he finds it full of faith, his word becomes a pledge and help toward salvation (2:3; 4:2).
living and active:
Emphasizes that God's word is the instrument of his will, i.e., he always does what he declares (Gen 1:3; Is 55:11).
sword:
A sword with both sides of the blade sharpened can maim and kill, but the divine word is more lethal still, for it can bring eternal death and destruction (10:26-31). • The danger that readers could "fall" by the sword (4:11) recalls the rebellion of the Exodus generation, which has dominated the thoughts of the author since 3:7. The sword imagery seems to be drawn from this episode: because Israel feared it would "fall by the sword" if the people followed the Lord into Canaan (Num 14:3), the word of God descended upon them as an oath of disinheritance and death (Num 14:20-34). Unable to reverse this tragedy, Moses had to warn the people not to advance into Canaan lest they "fall by the sword" (Num 14:43). Note that the oath Yahweh swears at the end of the Exodus period compares his word to a sharpened "sword" that cuts down his enemies (Deut 32:40-41; Ezek 21:8-17).
soul and spirit:
The spiritual elements of man. These are not hidden from God any more than the interior components of his body, such as his
joints and marrow.
See note on 1 Thess 5:23
. 
Back to text.

4:14-7:28
The next section of the letter examines the Melchizedekian priesthood of Jesus, showing how it supersedes the Levitical priesthood of Aaron. 
Back to text.

4:14 passed through the heavens:
Christ ascended into the most intimate presence of God in heaven (9:24). Jewish tradition sometimes speaks of multiple levels of heaven.
See note on 2 Cor 12:2
. 
Back to text.

4:15 without sinning:
One of several NT passages that assert the sinlessness of Jesus (2 Cor 5:21; 1 Pet 2:22; 1 Jn 3:5). Having triumphed over temptation as a man (Mt 4:1-11), he understands our struggles and is able to help us through them (2:18; 4:16) (CCC 612, 2602). 
Back to text.

4:16 confidence:
Or, "boldness" (CCC 2778).
the throne of grace:
The heavenly throne of the Father (8:1; 12:2), in whose presence Christ intercedes for us as high priest (7:25). • In ancient Israel, the Lord sat enthroned on the wings of the cherubim over the Ark of the Covenant (2 Sam 6:2; Is 37:16). Given the Tabernacle imagery that permeates the theology of Hebrews, the throne of the Father is probably envisioned as the Ark of the heavenly sanctuary (Rev 11:19). It is here that God gives us
mercy
after we sin and
grace
to keep us from sin (CCC 2795). 
Back to text.