In John 15:1-11, the Lord Jesus says that He is the vine, we are the branches. We must remain in him so that we can bear fruit. We must abide in Him, have connection with him so that we can bear fruit. Lord Jesus says that apart from him, we can do nothing.
Verse 10-11 says that if we abide in His love, He will give us his joy. The bible also says that in His presence, there is fullness of joy. In God’s presence, in the presence of Lord Jesus, there is fullness of joy. In order to bear fruit, we branches must constantly connect to the vine.