“And to know the love of Christ, which passeth knowledge, that ye might be filled with all the fulness of God.”
Ephesians 3:19

He says to be filled with all the fullness of God, you ought to know the love of Christ which passes knowledge, that seems contradictory until you realize he uses different Greek words as knowledge in the verse.
He says you can ginosko (have a revelation knowledge of) the love of Christ which passes gnosis (knowledge gotten via reading a book— scientific knowledge).
He wants you to know the love of Christ beyond head knowledge, beyond being able to theoretically elaborate on his love to being aware of, experiencing and living out that love.
In his fullness he loved us, and when we receive that love and love others, we are filled with his fullness!
It gets more exciting when you realize God’s love is already spilled inside of you, all that’s left is your consciousness of his love for you and your expression of that love to others:
“…We know this because God has poured out his love to fill our hearts through the Holy Spirit he gave us.” Romans 5:5, ERV

Bible Reading Plan: Isahiah 25 and Exodus 30