Commentaries:
There is one mediator, Christ. The Holy Spirit is referred to as the parakletos, the Comforter. It is the guide, leading us into all truth. Comforter means "one who goes alongside." If this were a personality, then one would begin to think that it is in a position somewhere between us and the Father. But the Bible makes o mention of anything of the kind. There is only one between us and God, and that One is the Son.
This is similar in form to I Corinthians 11:3, which shows that, of the Deities above us, only One stands between us and God the Father, that is, God the Son. This means that not even the Holy Spirit, sent to us as a Comforter, is a mediator.
If the Holy Spirit were God (equal to the Father and the Son), it would be an affront of the highest order to exclude "Him" from an intermediary role between us and the Father—especially when we consider that the Bible assigns us, mere human beings, an intercessory role between others and the Father. By prayer we are to intercede before the Father for one another, which is a form of mediation. We go to the Father in behalf of our brothers and sisters who are undergoing trial, difficulty, sickness, or whatever. The Holy Spirit is excluded from this role because it is not a personality, yet we are given it because we are personalities.
John W. Ritenbaugh
The Holy Spirit
Other Forerunner Commentary entries containing 1 Timothy 2:5:
Psalms 59:9-10
Psalms 59:16-17
John 8:44
John 15:4-5
Acts 5:3
Galatians 3:19