You must be in fellowship prior to your Bible study, so that the spiritual information you receive can become a source, of blessing to your soul and produce spiritual growth.
19 And[kai] if[ean] any man[tis] shall take
away[aphaireo] from[apo] the words[logos] of the
book[biblos] of this[touto] prophecy,[propheteia] God[theos] shall take away[aphaireo]
his[autos] part[meros] out of[apo] the book[biblos] of life,[zoe] and[kai] out of[ek] the holy[hagios] city,[polis] and[kai] from the things which are written[grapho] in[en] this[taute] book.[biblion]KJV-Interlinear
19 and if
anyone takes away from the words of the book of this prophecy, God shall take
away his part from the tree of life and from the holy city, which are written
in this book. NASB
In the last verse and in this verse, a very stern warning is made regarding the adding to or the taking away, from the message presented by this book and by the Bible on the whole.
At the end of the first century, John wrote this book in approximately 96 A.D. This book marks the close of the canon of scripture and the close of Gods revelation to humanity from that point forward.
There have been many apostate and fraudulent writings or holy spirit pretended manifestations since the first century. Those writings and things have been attempts to discredit God, Christ, and the overall message and plan contain in the Bible, or to self promote some activity or organization.
From false books to entire false religions, Satan, through many human agents, has tried to modify, dilute and destroy the teaching of the scriptures.
But through atrocities and plagues, through dark ages and enlightenment, through indifference and delusion, and through numerous invented religions and cults and philosophies, the message of Christ has persevered and stood out above all other faiths and philosophies and opinions.
The one name known throughout the centuries, that of Jesus Christ, has far surpassed any and all other names, and the scriptures have withstood and maintained the utmost respect above all else, Ps 119:97; Ps 119:113,163,167; John 14:23, Ps 119:70; Ps 1:2; 119:77,92,174.
And though believers in general will make mistakes during their growth, this warning is addressed primarily toward those who deliberately try to promote false representations of the scriptures.
There is only one way to know the content of the Word of God, and that is by means of a daily study. Where there is no study, there is no learning and there is no knowledge, leaving only the invention of the imagination, which leads to the loss of blessing and worse.
Only arrogance would drive a person to such a bitter end.