John Calvin Commentary Isaiah 8:6

"Forasmuch as this people have refused the waters of Shiloah that go softly, and rejoice in Rezin and Remaliah`s son;" — Isaiah 8:6 (ASV)

Because this people has despised (or, disdained) the waters of Shiloah. So that Ahaz may not slumber in unfounded expectation, the Prophet suddenly breaks off his discussion concerning the general safety of the godly and then threatens punishment on unbelievers. Some think that he speaks against those who wished for revolutions, as it frequently happens that the multitude are not satisfied with their present condition and desire to have a new king. Those who are diseased often expect that by a change of place, they will be in better health. So perverse is the will of men that when matters do not go according to their desire, they look for a change in their condition, snatch at it eagerly, and hope to obtain some relief from it.

But I think that the Prophet’s meaning is more extensive and does not apply only to those who wished for a change; rather, his message is general and includes all ranks. For impiety and contempt of God almost universally prevailed, and he does not speak of a few persons or of a particular party, but of the main body of the nation.

I confess, indeed, that he excepts a few persons, servants of God, who will be mentioned later. However, this does not prevent Isaiah’s remonstrances from being directed against the whole nation, for since almost all were corrupted, he justly reproves them all.

The offense is that the people, distrusting their own weakness, sought increased wealth and increased forces. He says, therefore, that they despised the waters of Shiloah, because the Jews despised and disdained their condition.

And their joy was to Rezin and Remaliah’s son. Some translate it as 'with Rezin,' but the preposition 'to' more fully expresses the perverse desire. He means that the Jews, perceiving that they did not have strong fortresses, looked in another direction and longed for the wealth of the kingdom of Israel. Seeing their small number and their poverty, they trembled and placed no confidence in God, relying only on outward assistance. They thought that they would be perfectly safe if they had a king as powerful as the Israelites had. Thus they rejoiced in the riches of others and in longing for them.