This is a citation from Zenock. Zenock’s citation plays an Old Testament theme of the anger of God against a rebellious Israel. It is in that context that we should see the anger of God. The important piece of information is once again the intermediary function of the Son. This more explicit teaching may have been unique to the Northern kingdom.
Application to Alma’s discourse: This verse is important for being the second brass plate prophet to mention the Son, and the importance of the Son. This gives these farmers two witnesses besides Alma. The anger of the Lord is not applicable in this case, indeed, the Lord would be quite pleased with the humility of the people. How might they have understood the anger of the Lord? They would likely have interpreted this verse in this context as an anger at their unbelief in the Son, and the reason for the arrival of Alma to teach them of the Atoning Messiah.