Romans 8:26
Likewise the Spirit also helpeth our infirmities: for we know not what we should pray for as we ought: but the Spirit itself maketh intercession for us with groanings which cannot be uttered.
 

Comments:

It is assumed by many today that this an example of the Holy Spirit interceding for us with groanings that cannot be heard.  The translators obviously thought this as well because the word "spirit" is capitalized in the KJV and many others.  The immediate problem with this is found with something else Paul wrote to Timothy in 1 Timothy 2:5
"For there is one God, and one mediator between God and men, the man Christ Jesus;"

The first and most obvious hurdle is to explain how there can be two mediators/intercessors between man and God.  The Greek words for mediator and intercessor are not the same.  The Greek word for "intercession" in Romans 8:26 is huperentugchano (hoop-er-en-toong-khan'-o); which means to intercede in behalf of and this is the only time this word is used in scripture.  The Greek word for "mediator" in 1 Timothy 2:5 is "mesites" (mes-ee'-tace); which is a go-between, i.e. (simply) an internunciator, or (by implication) a reconciler (intercessor).  The two words appear to be synonyms. 

The next hurdle is to demonstrate why the Holy Spirit is inferred in this context.  The word "Holy" does not appear in the original language.  The Holy Spirit is not mentioned as such by Paul in this verse so in order to infer the Holy Spirit, it is necessary to use other scripture in support of this inference.  Those who support the idea of the Holy Spirit intercessor point to Paul's writing in Galatians 4:6, "And because ye are sons, God hath sent forth the Spirit of his Son into your hearts, crying, Abba, Father".  It is said that the "Spirit of His Son" is indeed the Holy Spirit and that this justifies the inference of the Holy Spirit in Romans 8:26.  There are some difficulties with this in that this is the only place in scripture where the words "Spirit of His Son" occur in the KJV, NKJV, ASV, NASB and many others.  So then the task becomes, why do we infer that the "Spirit of His Son" is indeed the Holy Spirit and not just the disposition of Jesus?

Romans 8:23 says we groan within ourselves, this is the spirit of man being introduced into the context.  What does scripture say elsewhere about the spirit of man?  The spirit of man is the Lord's lamp, searching the innerman (Proverbs 20:27). The spirit of man can be renewed (2 Corinthians 4:16). The spirit of man can pray (1 Corinthians 14:14). The spirit of man groans within his tent of flesh (2 Corinthians 5:1-4; Acts 7:34). Jesus, as a man, groaned within (John 11:33ff). The spirit of man can lust (Galatians 5:17). The spirit of man wars (Romans 7:22-24). The spirit of man, the inward man, does more than we give it credit for.

Romans 8:23 says we groan within ourselves ... then in verse 26 the spirit of the context is helping.  And the very same spirit that is doing the groaning is unable to express itself in words.  Where in scripture can we find support for the Holy Spirit being unable to express Himself to God so that He has to groan?  The spirit in Romans 8:26 cannot be Deity, the Holy Spirit. 

Moreover, we know that it is not necessary for Deity to dwell in human flesh in order for God, the Father to hear prayers.  God heard the prayers of Cornelius and sent Peter to preach the gospel to him and his household.  This is also true for every saint whoever lived prior to and after the cross of Christ. God indeed heard their prayers. God already knows what is in the mind of man without having Deity, the Holy Spirit, reveal it for Him.

What Paul is saying in this context is that when a person is unable to express himself adequately, the spirit of that man's groaning is interpreted by God in the place of the words he cannot express.

This is a very comforting verse of scripture in that it makes God personally aware of our emotional state of mind and that He knows and hears what we need even when we are unable to express ourselves.  We have access directly to the Father through our one mediator, Jesus Christ.