What are the essential elements of eucharistic adoration? It is worshiping God, Who is thought to be extraordinarily present in created matter (what was formerly bread and wine). It involves God and His creation: worship of God present in and through His creation. Can a similar thing be found in Holy Scripture? It certainly can:

God Specially Present in Fire
Exodus 3:2, 6 (RSV) . . . he looked, and lo, the bush was burning, yet it was not consumed. . . . [6] And he said, “I am the God of your father, the God of Abraham, the God of Isaac, and the God of Jacob.” . . . (cf. Acts 7:30-33; Dt. 4:12, 15; 5:4-5; Mk 12:26; Lk 20:37)

Exodus 13:21 And the LORD went before them . . . by night in a pillar of fire to give them light, that they might travel by day and by night; (cf. 14:24; 40:38; Num 14:14; Dt 1:32-33; Neh 9:12, 19)

Exodus 19:18 And Mount Sinai was wrapped in smoke, because the LORD descended upon it in fire; . . . (cf. 24:17; Dt. 5:22; 9:10; 10:4)

God Specially Present in the Shekinah Cloud / “Glory of the Lord”
Exodus 13:21 And the LORD went before them by day in a pillar of cloud to lead them along the way, . . . (cf. 14:24; 16:10; Dt 1:33; 31:15; Ps 99:7; Neh 9:12, 19)

Exodus 24:16 The glory of the LORD settled on Mount Sinai, and the cloud covered it six days; and on the seventh day he called to Moses out of the midst of the cloud. (cf. 34:5; Num 11:25; Dt 5:22)
1 Kings 8:11 . . . the glory of the LORD filled the house of the LORD. (cf. 2 Chr 5:14; Ezek 10:4, 18)

God Specially Present Above the Ark of the Covenant
Exodus 25:22 There I will meet with you, and from above the mercy seat, from between the two cherubim that are upon the ark of the testimony, I will speak with you . . . (cf. 30:6; Lev 16:2; Num 7:89; 1 Sam 4:4; 2 Sam 6:2; 2 Kgs 19:15; 1 Chron 13:6; Ps 80:1; 99:1; Is 37:16; Ezek 10:4; Heb 9:5)

God Adored and Worshiped Through Fire, the Cloud of His Glory, the Tabernacle (“Tent”) and Temple
Exodus 33:10 And when all the people saw the pillar of cloud standing at the door of the tent, all the people would rise up and worship, every man at his tent door. (cf. 40:34-38; Lev 9:4-6, 23; Num 14:10, 14; 16:19, 42)

Numbers 20:6 Then Moses and Aaron went from the presence of the assembly to the door of the tent of meeting, and fell on their faces. And the glory of the LORD appeared to them, [this “glory” was manifested by a cloud: Ex 24:16; 40:34-35; 1 Kgs 8:11; 2 Chr 5:14; Ezek 10:4]

2 Chronicles 7:1, 3 When Solomon had ended his prayer, fire came down from heaven and consumed the burnt offering and the sacrifices, and the glory of the LORD filled the temple. . . . [3] When all the children of Israel saw the fire come down and the glory of the LORD upon the temple, they bowed down with their faces to the earth on the pavement, and worshiped and gave thanks to the LORD, . . .

God Adored and Worshiped Through the Ark of the Covenant
Joshua 7:6 Then Joshua rent his clothes, and fell to the earth upon his face before the ark of the LORD until the evening, . . .

1 Kings 3:15 And Solomon awoke, and behold, it was a dream. Then he came to Jerusalem, and stood before the ark of the covenant of the LORD, and offered up burnt offerings and peace offerings, and made a feast for all his servants. (cf. 2 Chr 5:6)

1 Chronicles 16:1-2, 4 And they brought the ark of God, and set it inside the tent which David had pitched for it; and they offered burnt offerings and peace offerings before God. [2] And when David had finished offering the burnt offerings and the peace offerings, he blessed the people in the name of the LORD, . . . [4] Moreover he appointed certain of the Levites as ministers before the ark of the LORD, to invoke, to thank, and to praise the LORD, the God of Israel. (cf. 2 Sam 6:17)

As we see, the Bible has many indications of a local presence of God in physical things (fire, smoke, ark of the covenant, and the tabernacle and temple), and of worship of God through those physical objects.

 Now that God has taken on human flesh, it’s not implausible at all for Him to choose to be present under the appearances of bread and wine.

 From the above biblical data we see that people including Moses, Aaron, Joshua, David, Solomon, and the Levite priests worshiped and adored God in fire, clouds, tabernacle, temple, and the ark of the covenant, and physically / bodily expressed adoration.

 It should also be noted that three of the five created things mentioned above were man-made (tabernacle, temple, and ark of the covenant). Moreover, the passages with the ark and temple also entail veneration or worship of God in conjunction with a statue. The cherubim on top of the ark of the covenant were little statues of angels. Statuary was also present in Solomon’s temple.

 Levite priests thanked and praised God before the ark of the covenant (1 Chr 16:4), just as Catholics genuflect and bow before the Holy Eucharist, and adore the Lord therein. King David “offered burnt offerings and peace offerings before the LORD” next to the ark (2 Sam 6:17), which is a precursor of the Sacrifice of the Mass. Catholic practices are essentially nothing that hadn’t been done 3,000 or more years ago. They are made far more meaningful, however, after the incarnation and crucifixion and Resurrection of our Lord Jesus Christ.