Charles Ellicott Commentary Hebrews 3:15

"while it is said, To-day if ye shall hear his voice, Harden not your hearts, as in the provocation." — Hebrews 3:15 (ASV)

If you will hear. — Rather, as before (Hebrews 3:7), if you shall hear. The true connection of this verse is not easily decided. By many it is held that the words should be joined with what follows, and commence a new paragraph; but this does not seem probable. Either Hebrews 3:14 is parenthetical, so that this verse emphasizes the reference to today in Hebrews 3:13; or the thought of the writer is that we must hold fast the beginning of our confidence in the presence of this divine warning—while day by day these words are addressed to us anew.