Charles Ellicott Commentary Hebrews 3:13

"but exhort one another day by day, so long as it is called To-day; lest any one of you be hardened by the deceitfulness of sin:" — Hebrews 3:13 (ASV)

While it is called To day.—Literally, as long as the “to-day” is called (to you), lest any one of you be hardened by deceit of sin. As long as they heard the word of God speaking in Scripture, To-day if ye shall hear, so long is the way of obedience open to them. Sin is here personified as the Deceiver (Romans 7:11), alluring from God by the offer of pleasures (Hebrews 11:25), or persuading that forbearance and respite (Exodus 8:15; Ecclesiastes 8:11) imply the absence of a Living God.