This is the first part in what may well be a series on miracles, etc. Several of the comments have flagged up that it's an area that needs explaining. It's going to be useful to first look at what the word "miracle" means in the Bible before we look at some of the implications...
The English word "miracle" does not occur in the original text of the Bible – it was written in Hebrew, Aramaic and Greek. So we should not automatically assume that the word "miracle" is necessarily the best translation of all the words used in the original. We need to think about what the words used for miracles actually mean. "Miracle" comes from the Latin word "miraculum", meaning an object of wonder. So, in English, a miracle is something that people are amazed at.
In the New Testament, there are three groups of words often translated as "miracle" or "miraculous" – δυναμις (dunamis), σημειον (semeion) and τερας (teras).
Dunamis comes from the same root as our word "dynamic", and is well translated by the English word "power". So a miracle where the word dunamis is used is something powerful that is done. An example is in Acts 8:13
Simon himself believed and was baptised. And he followed Philip everywhere, astonished by the great signs and miracles he saw.
Semeion means "sign". So a miracle where semeion is used is something that points someone or something out as special and different. In the verse above, the word translated "signs" is semeia – the plural of semeion.
Every time teras is used in the New Testament, it is paired with semeion. In the Greek translation of the Old Testament, it is used to translate the word mowpheth (see later), so it seems to mean roughly the same as dunamis.
All three are used in Acts 2:22.
Men of Israel, listen to this: Jesus of Nazareth was a man accredited by God to you by miracles (dunamis), wonders (teras) and signs (semeion), which God did among you through him, as you yourselves know.
These three words are not talking about different events. There are not some things that are miracles, some that are signs, and some that are wonders. In his gospel, John consistently uses the word semeion for all of them. These three words are complementary ways of describing the same events. Dunamis and teras emphasise God's power, and semeion emphasises the significance.
In the Old Testament, there are three Hebrew words used – mowpheth, 'owth, and pala' (I haven't yet set up this computer to be able to type in Hebrew).
'Owth means much the same as semeion, and is usually translated as "sign". Mowpheth means something like "wonder" or "display of God's power". Both can be seen used in Deuteronomy 26:8 and elsewhere, usually talking about the events connected with the Exodus.
So the LORD brought us out of Egypt with a mighty hand and outstretched arm, with great terror and with miraculous signs and wonders.
The Hebrew pairing of 'owth and mowpheth seems to be equivalent to the Greek pairing of semeion and either dunamis or teras. Just like in the New Testament, the words seem to refer to the same things – the same events at the Exodus were both signs and wonders, as were Jesus' miracles.
Pala' means something like "amazingly better than anything else". We see it used in Genesis 18:14
Is anything too hard (pala') for the LORD?
It is also used to mean things which are amazing because they are so difficult to do.
Before all your people, I will do wonders (pala') never before done in any nation in all the world.
So then, what shall we say a miracle is? The words used in the Bible to describe them point to this as a definition:
A miracle is a demonstration of (God's) power which acts as a sign to show that God is particularly at work.
There may of course be other purposes for the miracle as well. The crossing of the Red Sea also served the purpose of God rescuing his people from the Egyptians. But even then, God could have rescued the Israelites without a miracle. God said that the purpose was so that
The Egyptians will know that I am the LORD when I gain glory through Pharaoh, his chariots and his horsemen.
And afterwards we see the effect of the miracle on God's people.
And when the Israelites saw the great power the LORD displayed against the Egyptians, the people feared the LORD and put their trust in him and in Moses his servant.
God's stated purpose in the miracles of the Exodus was to use them as a sign to show people that he was (and therefore still is) God.
In fact, miracles in the Bible are always signs. The very first miracle where a person is involved in performing it is in Exodus 4, where God is giving Moses some signs:
"This," said the LORD, "is so that they may believe that the LORD, the God of their fathers – the God of Abraham, the God of Isaac and the God of Jacob – has appeared to you."
It is therefore not at all surprising that miracles in the Bible mostly occur when God is revealing more of himself to the people: in the work of Moses and Joshua (the Law), Elijah and Elisha (the Prophets), Jesus and the apostles (the Gospel).
I'll think about the implications of this and look at some examples in more detail another time.