The intercession of Christ

Consequently, he is able to save to the uttermost those who draw near to God through him, since he always lives to make intercession for them (Heb 7:25).

This is a deceptively simple verse. 

A. The first clause could mean two different things:

1. It might have a modal or qualitative meaning. It might mean Christ is able to completely save those who come to him. Not just assisting them in their pilgrimage. Not just a necessary condition. Rather, what he provides is all-sufficient to ensure their salvation. 

And that interpretation can be supported by the general theology of Hebrews, which lays great stress on the sufficiency and finality of the atonement, in contrast to the deficient nature of the old covenant. Moreover, the efficacy of the atonement is grounded in something absolute–the power of an indestructible life (Heb 7:16).

This might complement the temporal meaning (see below). Because the atonement is intrinsically sufficient, it's sufficient for now and for eternity. 

2. Or it might have a temporal or quantitative meaning: "for all time". Christ is always available to save those who come to him. And that interpretation receives support from the next clause. 

Moreover, the quantitative meaning can, in turn, have two different senses or applications:

i) It might refer to the same recipients. For instance, Christians remain sinners, so throughout life they never cease to need the redemptive work of Christ to atone for their sins: past, present, and future. Even–or especially–in heaven, the saints will never face the prospect of divine judgment. 

ii) Or it might have futuristic orientation. Perhaps it refers to future generations. Christ isn't merely alive to save Christians who were contemporaneous with the author of Hebrews, but Christians throughout the course of church history. On that view, Hebrews includes a futuristic eschatology.  

That's a sense in which the work of Christ can be both finished and continuous. 

B. The second clause could mean two different things:

1. It might have general reference to divine intervention. For instance, Jesus responding to petitionary prayer. 

And that interpretation has support from the general theology of Hebrews, which stresses God's providential preservation of the faithful, as they face trials and tribulations. Indeed, it is God who keeps them faithful (e.g. 2:18; 4:16). 

2. It might have specific reference to the application of the atonement. 

And that interpretation has support from the general theology of Hebrews, with its focus on the priestly office of Christ (vv26-28; 1:3; 2:17; 9:26,28).

(1) and (2) are complementary. Jesus sits at the right hand of God (1:1-14), so he can dispense favors. Moreover, he's not merely a priest, but a sympathetic priest. He knows firsthand what his people face (2:10-18; 4:14-16). His humanity and deity combine to make him an ideal intercessor. Omnipotent and empathetic.  

Finally, it's unnecessary to choose between these interpretation options, since they all have a foundation in the overall theology of Hebrews, and there's no antecedent reason to suppose the author felt the need to exclude those truths.