Signs and Wonders
The English word miracle is derived from the Latin word miraculum which literally means a marvelous event. The Bible is filled with God's miracles, known variously as signs or wonders, as also accomplished by various of His servants by means of the Holy Spirit - no human has miraculous power of their own. There also were, and are, numerous Satan-empowered "miracles" or outright frauds (e.g. "weeping" or "bleeding" Roman Catholic religious statues fall under either or both of these categories, since, in the Second Commandment, God plainly declares that humans are never to make or possess Images and Idols. See the logic? God would never perform a miracle to His glory through something that He has outlawed for religious use), that although sometimes seemingly spectacular, could never surpass those of God's true servants.
Many of God's true servants during the Old Testament period were as powerful in signs and wonders as any that came later:
"So Moses and Aaron went to Pharaoh and did as The Lord commanded; Aaron cast down his rod before Pharaoh and his servants, and it became a serpent." (Exodus 7:10 RSV) (see also Who Was The Exodus Pharaoh? and The Ten Plagues)
"Then spoke Joshua to The Lord in the day when The Lord gave the Amorites over to the men of Israel; and he said in the sight of Israel, "Sun, stand thou still at Gibeon, and thou Moon in the valley of Aijalon." And the sun stood still, and the moon stayed, until the nation took vengeance on their enemies." (Joshua 10:12-13 RSV) (see Joshua's Long Day)
"But Elijah answered the captain of fifty, "If I am a man of God, let fire come down from heaven and consume you and your fifty." Then fire came down from heaven, and consumed him and his fifty." (2 Kings 1:10 RSV)
"So Elisha died, and they buried him. Now bands of Moabites used to invade the land in the spring of the year. And as a man was being buried, lo, a marauding band was seen and the man was cast into the grave of Elisha; and as soon as the man touched the bones of Elisha, he revived, and stood on his feet." (2 Kings 13:20-21 RSV)
The miraculous power of the Holy Spirit was also evident through the New Testament, from Jesus Christ Himself, to His chosen servants:
"Men of Israel, hear these words: Jesus of Nazareth [see Nazarene], a man attested to you by God with mighty works and wonders and signs which God did through Him in your midst, as you yourselves know - this Jesus, delivered up according to the definite plan and foreknowledge of God, you crucified and killed by the hands of lawless men. But God raised Him up, having loosed the pangs of death, because it was not possible for Him to be held by it." (Acts 2:22-24 RSV) (see Resurrections)
"But Peter put them all outside and knelt down and prayed; then turning to the body he said, "Tabitha, rise." And she opened her eyes, and when she saw Peter she sat up. And he gave her his hand and lifted her up. Then calling the saints and widows he presented her alive." (Acts 9:40-41 RSV)
"And a young man named Eutychus was sitting in the window. He sank into a deep sleep as Paul talked still longer; and being overcome by sleep, he fell down from the third story and was taken up dead. But Paul went down and bent over him, and embracing him said, "Do not be alarmed, for his life is in him." (Acts 20:9-10 RSV) (see Paul's First Missionary Journey, Paul's Second Missionary Journey and Paul's Third Missionary Journey)
"The signs of a true Apostle were performed among you in all patience, with signs and wonders and mighty works." (2 Corinthians 12:12 RSV)
Beware Of False "Miracles"
Satan has been enabling sorcerers since the beginning, but the time just prior to The Return Of Jesus Christ will be the most spectacular in Satanic "miracles":
"Then Pharaoh summoned the wise men and the sorcerers; and they also, the magicians of Egypt, did the same by their secret arts. For every man cast down his rod, and they became serpents. But Aaron's rod swallowed up their rods." (Exodus 7:11-12 RSV) (see Jannes and Jambres)
"And then the lawless one will be revealed, and The Lord Jesus will slay him with the breath of His mouth and destroy him by His appearing and His coming. The coming of the lawless one by the activity of Satan will be with all power and with pretended signs and wonders, and with all wicked deception for those who are to perish, because they refused to love the truth and so be saved." (2 Thessalonians 2:8-10 RSV) (see Revelation 13 and Prophecy)
Fact Finder: What were some of the miracles done by Jesus Christ?
See Miracles Of Jesus Christ