There are two great basic reasons to be filled with the Spirit of the Lord. One is to have more access to Who He is. Another is to give Him more access to who you are.
Once isn’t all there is, either. Be refilled at every opportunity. There are rooms in the dwelling place you call your heart that He has not been given the keys to, and they are locked. He wants to be there as much as He wants to sit in the formal living room, where all the furniture is covered with plastic and the big fat family Bible sits on the coffee table.
He isn’t afraid of any of the rooms in our hearts, and we shouldn’t be afraid of His presence bringing light into the darkest corners of any of them. He wants the place to be full of Life and Light and Love.
He wants the keys.
I pray that He may grant you, according to the riches of His glory, to be strengthened with power through His Spirit in the inner man, and that the Messiah may dwell in your hearts through faith. I pray that you, being rooted and firmly established in love, may be able to comprehend with all the saints what is the length and width, height and depth of God’s love, and to know the Messiah’s love that surpasses knowledge, so you may be filled with all the fullness of God.
(Ephesians 3:16-19 Holman Christian Standard Bible ®©)