The identity of the “Restrainer” is a difficult problem in reading the apocalyptic section of 2 Thess 2. Paul says there that the Man of Lawlessnness cannot be revealed until the “restrainer” is removed. The problem is that he does not explicitly state who / what the restrainer is. Both the restraining power and the mystery of lawlessness are active at the time Paul writes. The restrainer must therefore be something that was active at the time of Paul and will continue to be active until the Day of the Lord. As a result, there are a number of suggestions as to the identity of this restrainer / restraining power.
There are two issues that need to be resolved with respect to the identity of the restrainer. First, there are lexical issues: What does the verb κατέχω mean? It can mean to hold back or restrain, but also “to hold fast, keep secure.”
Secondly, and perhaps more problematic, there are grammatical issues. In verse 6, Paul uses a neuter singular participle, but in verse 7 he uses a masculine singular participle. These two words should not refer to the same thing according to the rules of the Greek language. The first must have neuter referent, the second a masculine. The many suggested alternatives for understanding this passage can be categorized as taking the restrainer as a good force or an evil force.
From the time of Tertullian on, the neuter participle was taken as a reference to the Roman empire, and the masculine to the emperor himself. The verb means “to restrain,” therefore it is the rule of the Roman empire (or the rule of law, God ordained political order, etc) that restrains the chaos of the man of lawlessness from being revealed. The primary problem with this view is that Paul does not have a political rebellion in mind, but rather a religious apostasy, a rebellion against God. It is also difficult to see Paul claiming that the fall of Rome will be the beginning of the tribulation period and the power of the Anti-Christ.
Oscar Cullman, followed by T. Munck argue that the neuter participle is the preaching of the Gospel, and that the masculine participle is Paul himself as the key leader of the evangelical outreach in the first century. There is a serious problem with this view in the fact that Paul appears to believe that he will participate in the return of Christ (1 Thessalonians 4:13ff), this interpretation would need to have Paul taken out of the way before the beginning of the Day of the Lord.
I . H. Marshall defends this position by accepting the first participle as the preaching of the gospel, but changing the identification of the second to something other than Paul. Essentially he sees the God as restraining the forces of evil in the present age so that the preaching of the gospel can be fully accomplished. The force that is holding back evil is an angel or some spiritual being working on God’s behalf. This presupposes the idea that the gospel must be preached to the whole world before the Day of the Lord, which is simply not a Pauline requirement for the Day of the Lord. This position is appealing since it makes God the restraining power, but one must deal with the “taking away” of the restrainer. God could not be removed, although his role as a restrainer may be.
Roger D. Aus (JBL 96 : 537-553) attempts to make 2 Thessalonians reliant on Isaiah 66 in a number of places, therefore the source of the restrainer also found in Isaiah. While the word does not appear in the LXX, 66:9 does talk about the shutting up of the womb as an image for the delay in restoring the fortunes of Israel. Aus argues that Paul is freely translating the MT at this point, using katexw to mean delay of the Day of the Lord. While it is possible that the verb could be used to translate the Hebrew of Isaiah 66:9, it is far from the most obvious choice, and Paul simply uses the verb without any modification.
Charles Gilbin devotes an entire monograph to 2 Thessalonians 2 and develops a unique theory concerning the problem in the church as well as the identity of the restraining power. Gilbin sees a specific charismatic prophet within the church that has delivered the prophetic message that the Day of the Lord has begun. He therefore argues that katexw in the neuter has the sense of a prophetic seizure, and that the masculine pronoun refers to a false prophet. There are several problems here. katexw only has the sense of a prophetic seizure in the passive, both verbs are active here. Additionally, it is hard to understand why Paul would argue that the entire Day of the Lord is held in check until a single false prophet in a small local is taken out of the way.
As early as Darby (Notes, 452), the restrainer has been identified as the Holy Spirit in the Church. Walvoord, for example, argues in his prophetic writings that the restraining power is the Holy Spirit. This is not essentially different than I. H. Marshall described above, although Darby and other following Dispensationalist have made far more of this than Marshall would allow. If the restrainer is the Holy Spirit, then this passage becomes a clear argument in favor of a pre-tribulational rapture. The Holy Spirit is restraining the satanic influences in the world through the activity of the Church the Body of Christ. When the Body of Christ is removed from the world, the Satan is free to attack the world through the Anti-Christ.
Obviously this is a powerful argument for the pre-trib position. But is the Restrainer the Holy Spirit? Is that what this passage is really saying? It can be objected that the grammar of the passage makes the identification of the Holy Spirit as the restrainer impossible since the restrainer is masculine and the word for Spirit is neuter. If the genders are properly interpreted, they need to refer to two different things, albeit coordinated things. An additional problem is that the Holy Spirit is not explicitly mentioned in the passage. The gospel is (in chapter 1), and the forces of evil are clearly in the context, but the Holy Spirit is not.
In the most recent revival of this argument, Charles Powell (BibSac 154 : 321-333) sees the preaching of the Gospel as a part of the restraining force, but settles on the first referring to the Spirit and the second to God, with not contradiction based on the Trinity. He notes that in John 14:26 the Holy Spirit is called ho paravkletos, a masculine noun referring the neuter pneuma. This avoids any grammatical difficulties, and sounds quite a bit like I. H. Marshall.
It may be objected that the Old Testament very clearly indicates that the Holy Spirit will be active in the tribulation (Joel 2, for example.) If he is removed at the beginning of the Tribulation, how can he be “poured out” as Joel predicts? It is possible to argue that the restraining function of the Spirit through the Body of Christ will end at the rapture, although the functions of empowerment for ministry or prophecy will remain. Obviously God, who is omnipresent, cannot be “removed,” therefore there is some sort of shift in activities, such as at the time of the Flood.
Therefore it is best to conclude that the Restrainer power is God, through the Holy Spirit and the positive effects of the preached Gospel. The Spirit is active in the world as a preserving agent, a ministry that will end at the time of the Rapture, allowing the events of the tribulation to unfold.