The concept of "Today" emerges directly from the quotation of Psalm 95 in Hebrews 3:7-11: "Today, if you will hear His voice, do not harden your hearts as in the rebellion." This psalm is identified by the Jews as a Sabbath psalm, since its first six and three-quarter verses call for coming together to praise God before ending with this strong exhortation. Because of this connection, "today" applies especially well to the Sabbath, functioning as a weekly reminder to take stock of one's walk with God. Yet the word carries a broader application as well, extending to the entire time of God's calling; if one is able to hear God's voice spiritually, this exhortation applies personally and continuously. Central to the meaning of "today" is a sense of immediacy. The matter at hand cannot be postponed to some more convenient future moment—not after a vacation, a promotion, the children leaving the house, or retirement. What the author urges must be considered right now, and with even greater urgency if one recognizes in oneself the same tendencies toward drifting and apathy that afflicted the original Hebrew audience. This urgency is reinforced in Hebrews 3:13, which instructs believers to "exhort one another daily, while it is called Today, lest any of you be hardened through the deceitfulness of sin." The repetition of "today" here underscores that guarding against spiritual hardening—what is described as a kind of spiritual sclerosis—must be a daily effort, not an occasional one. This is because unbelief and hardening can progress without the person's awareness, much like a silent buildup within the arteries that produces no outward symptoms until the condition is severe. The author's insistence on "today" is thus a call to continual self-examination, so that something spiritually fatal does not develop unnoticed. This theme of "today" connects directly to the broader message concerning the end of an age and the danger of drifting. Just as the Hebrew audience faced mounting pressure and instability without recognizing how much their spiritual strength had eroded through neglect, so too can pressure and distraction in any era cause a gradual hardening of the heart toward God's voice. The exhortation to respond "today" is presented as the remedy to this drift, calling for immediate and ongoing attentiveness rather than delayed or occasional devotion. It ties together the warnings against unbelief, the deceitfulness of sin, and the danger of refusing Him who speaks, all of which develop slowly through the accumulation of lesser priorities crowding out God's word. In this way, "today" functions as both a specific reference to the Sabbath as a recurring point of spiritual accountability and a general summons to treat every moment as the appropriate time to hear and respond to God's voice. It reflects the urgency woven throughout the passage: that neglect, however subtle, has serious consequences, and that the appropriate response is not to wait for a future reckoning but to examine one's heart and realign with God's word continually, starting now.