The very first verse in this section of the song begins with a concept that can be challenging to understand about God. How can God take vengeance? How can God kill and wound (v. 39)? And how can God bring retributive justice against His enemies, in sharpening His sword, repaying those who hate Him, devouring flesh, and avenging His people (vv. 41–43)? It is crucial to understand these verses in light of the overall plan of the great controversy. God wants to save everyone, and the Bible is full of examples where God shows much more mercy than people do! But at some point, people reach a point of no return, where they have completely shut themselves off to the Holy Spirit. It is not that God is not trying to reach them, but they have made it impossible. For instance, before the flood, “the wickedness of man was great in the earth, and . . . every intent of the thoughts of his heart was only evil continually,” leaving God with no options with which to reach them (Gen. 6:5). Yet God takes responsibility for the ultimate punishment of sin. He does not want anyone to die, and He does everything He can to bring them back to Him. But many choose the way of death instead.
In addition, true love cares about justice done when loved ones are wronged. God is a God of justice. God makes things right when people have hurt the vulnerable and innocent. If a friend is raped and brutally murdered, you might forgive the rapist/murderer, but true love would not smooth things over and pretend nothing happened. True love demands justice. For those who accept His forgiveness, God took the penalty on Himself and died so that they do not have to experience the second death, but there are still consequences on this earth for heinous crimes done against innocent people. When you have experienced a situation like this, knowing that God will take vengeance as one who knows hearts and minds and will make things right, brings much comfort and peace.
Verse 43 is very different in the ESV and the NKJV, because certain manuscripts have a couple extra lines, which are included in the ESV. However, the basic concept is still the same: other nations and/or nature itself will rejoice as God restores the land and His people and avenges the wrongs done to them. Once again, anyone can be a part of God’s people, and will then experience His plan to right the wrongs and take vengeance against sin and suffering. The cursing psalms express similar sentiments, calling on God to bring justice and to finally win against evil. God wins, Satan loses; amen and amen!