God is spirit (John 4:24) and therefore has no body and is invisible to the human eye (John 6:46; Col. 1:15). How then can God make His presence known? In Old Testament times, He often revealed Himself by showing His “glory” (Hebrew, chabod; 2 Chr. 7:1).
The “glory of the LORD” was a term that the Hebrews used to describe the way in which God showed that He was present through visible signs such as thunder, lightning, clouds, or fire (for example, Ex. 3:1–6; 19:16–19; Num. 12:5; 2 Chr. 5:13–14). Keep in mind that the Hebrews were not responding to natural phenomena like these by calling them God, as some suppose. Rather, the invisible God was revealing Himself through means that humans could perceive.
When Christ was transfigured, He revealed God in perfect human form. Thus John could write that “the Word became flesh and dwelt among us, and we beheld His glory, the glory as of the only begotten of the Father” (John 1:14). And when the Holy Spirit came upon the first believers in the Upper Room, He revealed His presence through tongues of fire and other signs (Acts 2:1–4).
Two other ways that God reveals His glory are through the creation (Ps. 19:1) and through His people (Eph. 1:12; Col. 1:27). As believers in Christ, we are temples of God, and He wants to fill us with His glory (1 Cor. 6:19–20).