In John 15, Jesus and the 11 disciples (Judas having already left to betray Jesus) are gathered in the upper room partaking of the Passover feast. Jesus explained,
I am the true vine, and my Father is the vinedresser. Every branch in me that does not bear fruit he takes away, and every branch that does bear fruit he prunes, that it may bear more fruit.
Also, in verse 5:
I am the vine; you are the branches. Whoever abides in me and I in him, he it is that bears much fruit, for apart from me you can do nothing.
To bear fruit, according to the context, is to hear the words of Christ and act accordingly. Therefore, as a believer in Jesus, you should be be aware that salvation is through faith in Christ’s sacrifice on the cross, and be aware of what He teaches is the way a believer should live.
Some of Jesus’ teaching is obvious, don’t lust (Matthew 5:28, 29), don’t lie (Matthew 19:28), don’t murder (Matthew 5:22), and don’t reject Him (John 5:39, 40). However, He came to give life. As He told the Jewish people, “The thief comes only to steal and kill and destroy. I came that they may have life and have it abundantly.” There is more to bearing fruit than just doing good works or not sinning, as bearing fruit should be a lifestyle for a believer.
The abundant life is the fruitful life of following Jesus! This is summed up in John 15:7, 8:
If you abide in me, and my words abide in you, ask whatever you wish, and it will be done for you. By this my Father is glorified, that you bear much fruit and so prove to be my disciples.
Live your life as a follower (what disciple means) of Jesus, and in doing so, bear much fruit.