Deuteronomy 28:46 reads “These curses will be a sign and a wonder against you and your descendants forever.” (HCSB)
The entire chapter deals with some seriously scary stuff – the things movies and Armageddon are made of. God has promised that if His people fail to “carefully follow” all of His commands and statutes (Dt. 28:15 and multiple other places) this disastrous scene will come upon them.
The interesting thing is the use of the words signs and wonders. As a New Testament believer when I think of signs and wonders my first thoughts are of Jesus feeding the 5,000, healing people, raising the dead, etc. However, it seems that when we look at the broader picture in Scripture (Biblical Theology) we see that God uses signs and wonders in both positive and negative ways.
Signs and wonders can be negative (as here and on Pharaoh) or positive (Jesus in Gospels healing, etc.). In both cases; however, the signs and wonders point to The God of Creation who is attempting to get His people’s attention and demonstrate His glory through signs and wonders.
For those in the OT these signs and wonders (curses) should have driven them to seek repentance because they should have known they were judgments intended to provoke a return to their God.
In the NT, the signs and wonders should have driven those seeking God to the OT and thus realizing that Jesus’ demonstration of such signs and wonders was proof positive that the Kingdom of God had come, as prophesied in the OT.