I've been reading the prophet Joel today. God uses a foreign army to both judge His people (8th-6th century B.C. Judah) for a particular sin and to remedy the sin itself. What is the sin? They forgot that God was in their midst.
"Thus you will know that I am in the midst of Israel, and that I am the LORD your God, and there is no other...then you will know that I am the LORD your God, dwelling in Zion" (2:27; 3:17).
God gets their attention through a foreign army of invaders (1:6), which He calls "His army" (2:11) and "My great army" (2:25). It's interesting that, without the words of the prophet, the people would have regarded the invaders as their biggest problem. In reality, their biggest problem was that they had forgotten the presence of God in their midst.
I started reading Joel today for the same reason I always read Joel: Peter's sermon on the day of Pentecost. The apostle explains the Spirit's gift of tongues and the "speaking of the mighty deeds of God" by quoting Joel. "This is what was spoken of through the prophet Joel" (Acts 2:1-16). The sin of Joel (forgetting the presence of God) is also the sin of Judea on the day of Pentecost.
"If you had known in this day, even you, the things which may for peace! But now they have been hidden from your eyes. For the days will come upon you when your enemies will throw up a barricade against you, and surround you and hem you in on every side, and they will level you to the ground and your children within you, and they will not leave in you one stone upon another because you did not recognize the time of your visitation" (Luke 19:42-44).
After wandering in that spiritual wilderness 40 years that generation was destroyed for not knowing the God in their midst (40 years from Christ's ascension to the destruction of Jerusalem by the Romans in A.D. 70).
Church, may we not get so distracted by the "enemies" in our culture and political systems that we forget the greater reality of the God in our midst. Saint, distraction is one of my greatest enemies - if it's yours, as well, let's pray for each other that we don't forget the greatest blessing imaginable that is ours now and forever in Christ: the presence of God Himself in the Person of the Holy Spirit!