<p>3:15 <i>It is said: Today, if you hear his voice, do not harden your hearts, as in the rebellion</i>- The idea of &quot;today&quot; as expounded on :7 is that if we right now hear the Lord's voice, we can rejoice that if today is our &quot;end&quot;, then we shall be saved. We have heard in essence the same voice as Israel heard in that the Gospel was preached to them as well as to us (4:2). &quot;The rebellion&quot; is a phrase used only elsewhere in :8, where it refers to the whole period of Israel's testing of God in the desert, rather than some particular moment of rebellion. But the quotation from Ps. 95:8 specifically uses the Hebrew word <i>meribah</i> for &quot;the rebellion&quot; or &quot;provocation&quot;. Their provocation at Meribah was that they had specifically challenged God to prove He was amongst them, despite having been given so many signs that He was; and they did this at a place called Meribah twice, at the beginning (Ex. 17:7) and at the end of the forty year wanderings (Num. 20:2-13). The observation is made in Ps. 78:18,41 that this latter testing of God was done &quot;in their heart&quot;, and it is the heart which is Paul's concern in this section. The hardening of hearts was therefore in refusing to perceive all the evidence which God had already given in Christ and indeed in the miraculous signs which had been witnessed by the Hebrew Christians. Perhaps Paul felt that the 40 year period from the Lord's death was coming to a close, and the Hebrew Christians likewise at the end of a similar period were testing God and desiring to return to Egypt, which is what happened at Meribah (Num. 20:2-13). But the element of 'return' was in that they were returning to Judaism, which Paul sees as 'Egypt'. Stephen made the same connection in his speech (see on 1:1).</p>