Because He Came ...
I can be fruitful.
John 15:5 NKJV“I am the vine, you are the branches. He who abides in Me, and I in him, bears much fruit; for without Me you can do nothing."
John 15 is talking about Jesus and the importance of abiding in Him - spending time with Him in bible study, prayer and just basking in His presence. When you are quiet and still before Him, you can hear what He says to you. If you follow His instructions, you'll bear fruit.
And what is fruit?
The fruit of the Spirit is love, joy, peace, long-suffering, kindness, goodness, faithfulness, gentleness, self-control. (See Galatians 5:22-23) Fruit. Not fruits. If you abide in Him, you will have ALL these attributes in your character.
And the world will know you've been with Jesus.