Hebrews 3:8

8.Then follows, Harden not your hearts By which words is intimated that our rebellion against God flows from no other fountain than willful wickedness, by which we obstruct the entrance of his grace, We have indeed by nature a heart of stone, and there is in all an innate hardness from the womb, which God alone can mollify and amend. That we, however, reject the voice of God, it happens through a spontaneous obstinacy, not through an external impulse, a fact of which every one is a witness to himself. Rightly, then, does the Spirit accuse all the unbelieving that they resist God, and that they are the teachers and authors of their own perverseness, so that they can throw the blame on none else. It is hence, however, absurdly concluded that we have, on the other hand, a free power to form the heart for God’s service; nay rather, it must ever be the case with men, that they harden their heart until another be given them from heaven; for as we are bent towards wickedness, we shall never cease to resist God until we shall be tamed and subdued by his hand.

As in the provocation, etc. It was for two reasons necessary for them to be reminded of the disobedience of their fathers; for as they were foolishly inflated on account of the glory of their race, they often imitated the vices of their fathers as though they were virtues, and defended themselves by their examples; and further, when they heard that their fathers were so disobedient to God, they were thus more fully taught that this admonition was not superfluous. As both these reasons existed even in the Apostle’s time, he readily accommodated to his own purpose what had been formerly said by David, in order that those whom he addressed might not imitate their fathers too much.

And hence may be learnt a general truth, that we are not to defer too much to the authority of the fathers lest it should draw us away from God; for if any fathers have ever been worthy of honor, no doubt the Jews possessed that preeminence; and yet David distinctly commanded their children to beware of being like them.

And I have no doubt but that he referred to the history recorded in Exodus 17:1 : for David uses here the two names which Moses relates were given to a certain place, מרבה Meribah, which means strife or provocation, and מסה Massah, which means temptation. They tempted God by denying that he was in the midst of them, because they were distressed for want of water; and they also provoked him by contending with Moses. Though indeed they gave many examples of unbelief, yet David selected this in an especial manner, because it was more memorable then any other, and also, because in order of time it followed for the most part the rest, as it evidently appears from the fourth book of Moses, where from chap. 10 to 20 a series of many temptations is described; but this narrative is given in the twentieth chapter. This circumstance increased not a little the atrocity of their wickedness; for they had often experienced the power of God, and yet they perversely contended with him, and renounced all confidence in him: how great was their ingratitude! He then mentioned one particular instance instead of many.