Matthew Poole and continuators on Hebrews 3:15

15 Whilst it is said, To day if ye will hear his voice, harden not your hearts, as in the provocation .

This is another circumstance of the Example of the Iews applied to them: That since now Christ is speaking to you, as he did to your fore-Fathers then; the same Voice concerneth you both, so, as not to morrow, or when you will, but To day, if you will believe what God speaketh to you by him, and hath recorded in his Word concerning his being the Messiah, and render not your selves deaf to God's Voice, or obdurate through Unbelief, as your fore-Fathers did, when their Unbelief and hardness of Heart imbitter'd God's Spirit against them, because acting in it against their solemn Vows and Engagements to him, so as to Apostatize from him.

Marginal references: Ver. 7.