"One thing I asked from HaShem, one thing that I will request; to dwell in the House of Hashem all the days of my life, and gaze upon the Pleasantness of HaShem, and to visit within His Temple." King David started speaking in the past tense -- "One thing I asked from HaShem" -- and then switched to the future tense -- "One thing I will request from HaShem." The entire span of his life, from his youth till his final years, King David continuously sought "one thing" -- to be in the Presence of HaShem! In contrast, most people frequently change their goals at every new stage of life. A young child wants candy, and when he gets a little older he wants a toy, and then a fancy bike. When he becomes an adult he wants a wife, and then a big house, and so on and so forth. However, King David had one solitary, unchanging request throughout his entire life. Specifically, King David longed and desired for one supreme and precious gift, "To dwell in the house of HaShem, all the days of my life."
A spiritually oriented person is singularly focused on the true, eternal joy of coming close to HaShem, "to dwell in the House of HaShem all the days of my life."
Envision King David praying, pleading, and singing to HaShem. Imagine how his entire heart and soul passionately longs to be constantly and eternally close to HaShem. See how King David celebrates "dwelling in the House of HaShem all the days of my life." Make HaShem the center of your life and come close to His endless wellspring of blessings, kindness, and the incomparable joy of being in His holy Presence.
(Based on the writings of the Chofetz Chaim)