One thing have I desired of the LORD, that will I seek after; that I may dwell in the house of the LORD all the days of my life, to behold the beauty of the LORD, and to inquire in his temple.
One thing ... that I may dwell in - not literal 'dwelling,' but spiritual (Psalms 15:1; Psalms 23:6; John 14:23; Revelation 3:12). To have a perpetual enjoyment of God's realized grace and presence (John 8:35). All other blessings are included in this, so that this one thing is, and shall always be, the Psalmist's ruling desire. The tabernacle, and subsequently the temple, symbolized the union between God and His true worshippers, dwelling in spirit with Him there.
To behold the beauty - or (to answer to the parallel, "to behold," etc.) to searchingly meditate thereon х baqeer (H1239)] - (namely, on His beauty: His beautiful grace, wisdom, and love, experimentally seen by His people, Psalms 90:17: "the goodness of the Lord," Psalms 27:13) in His sanctuary (Hengstenberg). The Hebrew, "to behold the beauty of the Lord," is literally, 'to behold IN it' х chaazah (H2372) with bª-] an idiom expressing the delight which gazing continually into it gives. Compare James 1:25. In the literal sense, not even the priests dwelt always in the sanctuary. What follows as the result of 'dwelling in the house of the Lord' is figurative (Psalms 27:5) - "In the time of trouble ... He shall hide me ... in the secret of His tabernacle;" therefore the dwelling in the house of the Lord must be figurative too. The being hidden by God in a secret place of safety, or sanctuary, is the result of spiritual abiding in and with Him.