"As for you, let that abide in you which you heard from the beginning.  If what you heard from the beginning abides in you, you also will abide in the Son and in the Father.  And this is the promise which He Himself made to us: eternal life."

John tells his readers about the path to righteousness... The path toward walking with God.

What does it mean to abide in what you have heard from the beginning?  John has been writing about walking in the light and following God's commandments.  This is what he means by abiding in Jesus:

Give up walking your path to success, as you see it - and begin walking the path that Jesus walked.  Live the life that Jesus lived.

Let's remember that life for a second.  Jesus life was full of purpose (God's purpose), and full of power (God's power) and full of sacrifice (sacrifice to God).  Jesus went to the furthest extreme for the sake of loving us.

If you seek righteousness - seek Jesus' lifestyle.