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.

I have always heard this verse interpreted as a reference to praying in tongues.  This seems unlikely, however, since tongues can hardly be described as “groanings,” and tongues are “uttered.”  So what is Paul talking about?  I’ve heard people groaning before, but even those groans are uttered.  I can’t even make sense of an unutterable groan.

And who is doing the interceding?  It’s commonly understood that the Spirit is interceding through human beings, but as I read the text, the Spirit makes intercession “for” us, not “trough” us.  If so, what does it mean to say the Holy Spirit groans?

Does anyone have any insight on the meaning of this passage they would like to share?