Genesis 3 - Curses
After "The Fall" God spoke several curses, and also blocked access to the tree of life.
Satan (and the Serpent)
And the Lord God said unto the serpent, Because thou hast done this, thou art cursed above all cattle, and above every beast of the field; upon thy belly shalt thou go, and dust shalt thou eat all the days of thy life: And I will put enmity between thee and the woman, and between thy seed and her seed; it shall bruise thy head, and thou shalt bruise his heel.
- Genesis 3:14-15 (KJV)
This curse is actually two-fold, e.g. for satan as well as for the serpent.
Why curse an animal?
This is purely symbolic of course. Satan used (possessed) the serpent to approach Eve, and God cursed everything that satan had touched, so we would never forget.
The phrase "upon thy belly shalt thou go", implies that this was not always the case, e.g. maybe originally the serpent had wings as Ellen White says?
Satan then assumed the form of a serpent, and entered Eden. The serpent was a beautiful creature, with wings; and while flying through the air, his appearance was bright, resembling burnished gold. He did not go upon the ground, but went from place to place through the air, and ate fruit like man. Satan entered into the serpent, who took his position in the tree of knowledge, and commenced leisurely eating of the fruit.
- Ellen White, Signs of the Times, January 16, 1879, par. 23
I'd say the serpent is easily the most hated animal on this planet, and the phrase "I will put enmity between thee and the woman" doesn't really need to be explained - ask any woman.
The phrase "enmity ... between thy seed and her seed" refers to enmity between satan (and his followers) and Jesus. Note that it says "her seed". This actually refers to Jesus, where the male counterpart was provided by God, and not man. Hence, Jesus is both the Son of God, as well as the Son of Man.
There is of course, also enmity between believers and non-believers. Mainly because believers remind non-believers that there is a God who holds people accountable.
The phrase "it shall bruise thy head, and thou shalt bruise his heel" refers to satan bruising Jesus' heel (on the cross), and to Jesus bruising satan's head (which is death).
Note that Adam and Eve were given curses they could repent from, but that satan was given the death sentence. This is because satan was already a hardened sinner at that point. His fate is sealed.
Unto the woman he said, I will greatly multiply thy sorrow and thy conception; in sorrow thou shalt bring forth children; and thy desire shall be to thy husband, and he shall rule over thee.
- Genesis 3:16 (KJV)
The multiplied sorrow and conception, may well be because every child now born has the knowledge of good and evil, which is obviously not a good thing.
The phrase "he shall rule over thee" refers to the changed relationship between Adam and Eve, e.g. they were equal at first, but because Eve misled Adam, now man rules over woman.
And unto Adam he said, Because thou hast hearkened unto the voice of thy wife, and hast eaten of the tree, of which I commanded thee, saying, Thou shalt not eat of it: cursed is the ground for thy sake; in sorrow shalt thou eat of it all the days of thy life; Thorns also and thistles shall it bring forth to thee; and thou shalt eat the herb of the field; In the sweat of thy face shalt thou eat bread, till thou return unto the ground; for out of it wast thou taken: for dust thou art, and unto dust shalt thou return.
- Genesis 3:17-19 (KJV)
The phrase "cursed is the ground for thy sake" refers to the increased difficulty of working the ground.
The phrase "for dust thou art, and unto dust shalt thou return" refers to death (see also "the tree of Life" below).
The Tree of Life
And the Lord God said, Behold, the man is become as one of us, to know good and evil: and now, lest he put forth his hand, and take also of the tree of life, and eat, and live for ever: Therefore the Lord God sent him forth from the garden of Eden, to till the ground from whence he was taken. So he drove out the man; and he placed at the east of the garden of Eden Cherubims, and a flaming sword which turned every way, to keep the way of the tree of life.
- Genesis 3:22-24 (KJV)
Not technically a curse, but definitely a consequence of The Fall.
God is clearly saying that He will not give Eternal Life to those who break His Law.
So death entered the world.
Wherefore, as by one man sin entered into the world, and death by sin; and so death passed upon all men, for that all have sinned:
- Romans 5:12 (KJV)
Note that we're not here on a holiday.
We live in a fallen (cursed) world.
Curses may seem cruel at times, but keep in mind that it's the very nature of suffering that leads us back to God.