“For if these things be in you, and abound, they make you that ye shall neither be barren nor unfruitful in the knowledge of our Lord Jesus Christ.”  
2 Peter 1:8

He says he expects us to neither be barren (unemployed, useless, inactive) nor unfruitful (result-less) in the knowledge of the Lord Jesus Christ.
He wants you to put your knowledge of the Lord Jesus to work, don’t just know him, do something about that knowledge- be active, not useless.
‘Jesus resurrected from the dead; glory!’ He wants you to know that as a fact and do something with that knowledge, put it to work: ‘If he came out of death, that means there’s no hopeless situation for you. If he came out of death itself, then no matter how deadly that sickness is, you can come out of it!’ That’s using your knowledge of Jesus and not just reciting it as a memory verse.
He also wants your knowledge to be fruitful, that means when you move from being inactive to using that knowledge, he wants you to produce results, now that you know that no sickness is too deadly for you to come out from, then you should be healed! That knowledge should produce results!
God wants his word to be more than just another religious book, he wants you to be his expression- putting the word to work and producing undeniable results; you’re born of the word!
In the main verse, he says you have a part to play in ensuring your reality is one of activity and result! There are things that should abound in you and you’d be made for life!