Francis Chan wrote a book entitled "The Forgotten God." It's about the Holy Spirit the third member of the triune Godhead. I haven't read it but I have been convicted about my own lack of acknowledgement for the work of the Holy Spirit in my life. Two areas of the Holy Spirit's influence are guidance for the believer and the ability to overcome sin. It is the Spirit who indwells every true believer that makes us able to have victory over the sin that besets us. It is the Spirit who guides our days and oversees our paths. It's interesting to me that I pray to the Father and to the Son but never to the Holy Spirit. It's as though He is indeed the Forgotten God.
I know many reformed people are concerned about some of the charismatic excesses that are far too prevalent. Christians can neglect the Spirit but they also can so emphasize His work that we fail to acknowledge the Father and the Son. Believers attribute manifestations that are more from the flesh or even the enemy to the Holy Spirit. I remember being in a charismatic church where a woman was barking like a dog intermingled with insane laughter. It made my flesh crawl and my spirit cringe. There is a balance in the trinity that the Bible emphasizes. Each member is fully God yet operates in different ways in a believer's life. It's a hard balance to maintain at times but through consistent study of God's Word and wisdom to discern there never need be any Forgotten God.