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.
11 And[kai] have[sugkoinoneo] no[me] fellowship[sugkoinoneo] with the unfruitful[akarpos] works[ergon] of darkness,[skotos] but[de] rather[mallon][kai] reprove[elegcho] them. KJV-Interlinear
11 And do
not participate in the unfruitful deeds of darkness, but instead even expose
them; NASB
The key to this verse is the word, unfruitful 'akarpos,' which means barren, without production, infertile, sterile.
Anything that is accomplished when out of fellowship, and thus out of the will of God, is unproductive, empty, useless, gives rise to no satisfaction, no accomplishment, no true joy, but only false perceptions of these things, and trouble to boot.
Therefore, pursuing these things would be like chasing after a rainbow, rolling dice that never win, hoping for things that will never be, pretending accomplishment that is not real, pursuing goals or objectives or desires that will never be attained.
But the big problem is in understanding just what unfruitful means. Most folks identify unfruitful as meaning sin, criminal activity, unacceptable social morals, and the like. And certainly these are unfruitful for they are not spiritual activities.
But the most unfruitful activity exists in being out of fellowship. For anything and everything that you do while out of fellowship, is works of the carnal nature, works of the sin nature, and are all unfruitful even if on the surface they seem good.
For example, helping a little old lady to cross the street seems like a good deed. But, when you are out of fellowship, it is a deed of the flesh, or classified as human good, and not divine good. When you do this while you are in fellowship, then your deed is classified as divine good, for it is done while under the energy of the Holy Spirit. This is a subtle distinction, but very real.
Most folks pursue the Christian life through their works, like going to church, going to prayer meetings, doing charitable work, posting scripture online, saying the right things in public, acting Christian, and these things alone, are not good, but evil disguised as good.
Remember the difference between the energy of the spirit and the energy of the flesh, lies in your obedience to Gods mandate to confess your sins on a regular basis, and in your pursuit of Gods mandated daily Bible study.
The combination of these last two things, confession and study, form the environment and foundation of your spiritual life. All things after that, namely your daily activities while in fellowship, are a result of your spiritual growth.
Good deeds are not spiritual growth or the spiritual life, but are a result of spiritual growth in the spiritual life.
To reject or ignore, or just simply forget Gods mandates, is a subtle form of arrogance and therefore serves evil.
Darkness is a word that often is used to describe and define evil. In darkness there is no light, no reference points, no ability to appreciate, no orientation, nothing.
So, it is mandated to avoid out of fellowship activity, which means that you should be in fellowship as much as is possible, or at least make the effort. But then this should seem obvious that you would avoid the worthless and pursue that which has value.