Keener writes, “While careful study of scriptures helps counter the unbridled subjectivism of popular charismatic excesses, study that does not lead to living out biblical experience in the era of the Spirit misses the point of biblical texts.” 
The Unbridled Subjectivism of popular charismatics excesses
This is the biggest problem among charismatics. There is much openings for inadvertent or temptations in going into excesses, because you are dealing with the supernatural which is by faith, a little blur, a little unclear. Unless you have clear doctrinal teachings that ground you, the feelings of the flesh will emerge once in a while, and somewhat overtakes the spirit within us. Because it’s blur, unclear, there seems to be room to ‘help’ the Holy Spirit, so to speak, making it completely unacceptable, deviant from the Scriptures. This causes great damage to the reputation of charismatics and Pentecostals. So much so many charismatics simply retrieve from it, effectively being by name charismatics. But functioning essentially as a non-charismatics. The sense I am taking to draw the line, is really in exercising the gift of the Holy Spirit that defines a so called Pentecostals or charismatics.
The key word here is “subjectivism”, which is the opposite of “objectivism”. Being subjective can become the opinion of the person doing it, instead of operating under the doctrinal watch of scriptures. Take for example, the entire ‘prosperity doctrine’ is popularized by some faith preachers that uses the power of the proclamation of the word of God because of the power in your confession. There is power in your spoken words, but it’s taken too far. So faith preachers recently in America just proclaimed that virus Covid 19 to disappear in the Name of Jesus in TV and when I saw that, it really looks like an excess of the faith preachers. This is being laughed upon by some reformed preachers in twitters, and it is causing damage to charismatics reputation. Confessing of the word is used in :
Romans 10 9 because, if you confess with your mouth that Jesus is Lord and believe in your heart that God raised him from the dead, you will be saved. 10 For with the heart one believes and is justified, and with the mouth one confesses and is saved.
The power of confession is used here for the Lordship of Jesus Christ, not for you to calm a storm, or heal a disease. There is espousing too much power which beings to God only and not for human confessional prayers. I like the Westminster confession that uses confessions for prayers of confessing sins etc. Luther is known for confessing sins by word of mouth in his struggle against the condemnation of sins in his own life.
Mark 11: 20 As they passed by in the morning, they saw the fig tree withered away to its roots. 21 And Peter remembered and said to him, “Rabbi, look! The fig tree that you cursed has withered.” 22 And Jesus answered them, “Have faith in God. 23 Truly, I say to you, whoever says to this mountain, ‘Be taken up and thrown into the sea,’ and does not doubt in his heart, but believes that what he says will come to pass, it will be done for him. 24 Therefore I tell you, whatever you ask in prayer, believe that you have received it, and it will be yours.
Jesus passed by a fig tree and he reached for some fruit but found none. In his disappointment and frustration, he cursed it. It withered. In that context, disciples told Jesus that the fig tree Jesus cursed had withered. There is an immediate effect of the spoken words of Jesus. He is also the one who spoke into being the world.
Genesis 1In the beginning, God created the heavens and the earth. 2 The earth was without form and void, and darkness was over the face of the deep. And the Spirit of God was hovering over the face of the waters. 3 And God said, “Let there be light,” and there was light. 4 And God saw that the light was good. And God separated the light from the darkness.
You see here “God said”. It’s the Trinity God, Father, Son and the Holy Spirit who spoke. Jesus was one of them.
Genesis 1:26 Then God said, “Let us make man in our image, after our likeness. And let them have dominion over the fish of the sea and over the birds of the heavens and over the livestock and over all the earth and over every creeping thing that creeps on the earth.”
You see the words “Let us..” its three persons, the Trinity of God.
The point here is Jesus as God spoke, the fig tree dried up. We, as Christians, who are humans, are in no way matching Jesus in our proclamation of our words.
Then Jesus says: 22 And Jesus answered them, “Have faith in God. 23 Truly, I say to you, whoever says to this mountain, ‘Be taken up and thrown into the sea,’ and does not doubt in his heart, but believes that what he says will come to pass, it will be done for him.
The point here is “Have faith in God”. Not “Go ahead and speak to anything by your mouth, and it shall be done”. You can say all you want, but without faith in God, nothing will happen. Its God who can do it, not you or me. The main object or subject here in this verse is faith in God. What drives this whole conversation teaching of Jesus is about Faith in God. Now faith is not something you pump up, but rather something you grow by experiencing. This is a very beautiful verse on faith:
Hebrews 12: 1Therefore, since we are surrounded by so great a cloud of witnesses, let us also lay aside every weight, and sin which clings so closely, and let us run with endurance the race that is set before us, 2 looking to Jesus, the founder and perfecter of our faith, who for the joy that was set before him endured the cross, despising the shame, and is seated at the right hand of the throne of God.
We get and grow our faith by looking to Jesus. Literally visionary spiritually, meditatively upon the scriptures.
Study that does not lead to living out biblical experience in the era of the Spirit misses the point of biblical texts
What Dr Craig Keener, a Pentecostal theologian, is saying is that studying the word of God is the first absolute requirement for us all Christians. However, if our study does not lead us to biblical experiences in the era of the Holy Spirit, we miss the point of biblical texts. Miss the point of studying scriptures. It’s like you study traffic laws, regulations, and the manual of using brakes, accelerator, steering wheel etc. from the books, but never got a chance to actually drive a car! It’s like learning all the skills of swimming by books on strokes, watching videos etc., but never got into water to experience water! You would never learn to swim.
The point of biblical texts point to the experience of the biblical texts. That’s the whole point. By right, as he said, all Christians are charismatics, because Jesus gave us all gifts (charismata) in Greek, and we all have at least one gift.
1 Corinthians 12:4–11 4 Now there are varieties of gifts, but the same Spirit; 5 and there are varieties of service, but the same Lord; 6 and there are varieties of activities, but it is the same God who empowers them all in everyone. 7 To each is given the manifestation of the Spirit for the common good. 8 For to one is given through the Spirit the utterance of wisdom, and to another the utterance of knowledge according to the same Spirit, 9 to another faith by the same Spirit, to another gifts of healing by the one Spirit, 10 to another the working of miracles, to another prophecy, to another the ability to distinguish between spirits, to another various kinds of tongues, to another the interpretation of tongues. 11 All these are empowered by one and the same Spirit, who apportions to each one individually as he wills.
Paul is saying here that all kinds of gifts, but the same Spirit. There are gifts of manifestation of the Spirit, wisdom, utterance, healing, miracles, prophecy, distinguish spirits, tongues, —all empowered by the one and same Spirit.
How many gifts operate in your church now? Honestly? Gifts are operating in preaching in manifestation of wisdom, knowledge generally, but the rest??
These are called the experiences of the bible, or biblical experiences in the era of the Spirit. We are in the era of the Spirit now. This is it. Go and run for them.
1 Corinthians 14: 1 Pursue love, and earnestly desire the spiritual gifts, especially that you may prophesy. 2 For one who speaks in a tongue speaks not to men but to God; for no one understands him, but he utters mysteries in the Spirit. 3 On the other hand, the one who prophesies speaks to people for their upbuilding and encouragement and consolation.
First pursue love. Then earnestly desire the spiritual gifts especially prophecy. Not just desire, but earnestly desire.
 Craig Keener, Spirit Hermeneutics, p 5 W B. Eerdmans Publishing Co., Grand Rapids, Michigan , 2016