It is a pure enchantment combo, which means the combo consist only by enchantment. The most important card of this combo is Humility, which is a very very powerful card not only in format EDH but also in format Legacy. Humility says that all creature loses all abilities and is a 1/1 creature, which means all creatures on board become useless, no matter how big the creature is and how strong the creature’s ability is. It is a killer of almost all creature deck. Something is noticeable is that the triggered ability when the creature enter the battlefield also become invalid, because when it enters the battlefield, it has already become 1/1 and lost all ability, so the triggered ability is also lost. This makes Humility hard to destroy for creature decks, since the most usual way to destroy an enchantment for a creature deck is to use the triggered ability when creature enter the battlefield.
The second piece of this combo is Dovescape, which counters all non-creature spell and put that many 1/1 tokens into play that is equal to its mana cost. Thus, all creature player cast will turn into 1/1 creature anyway. (creature spell will also be 1/1 because of humility).
The last thing you need is to kill these 1/1 creatures, Night of Souls’ Betrayal will help you to do that. All creatures will be 0/0 after -1/-1, so they will go to graveyard afterward. Here this combo is almost done, since all spells player cast will turn into 1/1 creature and go to graveyard immediately because the Night of Souls’ Betrayal.
You may have the question, I also can’t any spells, how can I win the game. Don’t worry your man land will help you win the game. Man land are lands that can turn into a creature. According to the rule of mtg, rewrite creature’s power or toughness is belong the 4th layer of the deciding creature’s power toughness. Both the Humility’s second ability and man land’s becoming creature ability are all the instance of rewriting creature’s power or toughness. So the one come into play later will go into effect, which means the power and toughness of the man land is not 1/1, it has its the original power and toughness and will not killed by Night of Souls’ Betrayal.
In fact, there is another way to win the game, which I suggest. There is a card called Enduring Ideal which can let you search library for enchatment card and put it into play every turn. The ability Epic is an interesting ability, which represents a spell ability and a delayed triggered ability. The spell ability is if the spell resolves, your can’t cast spell in the rest of game and the delayed triggered ability is at each beginning of your upkeep, copy this spell except for its epic ability. Note that the delayed treggered ability is a copy of spell which isn’t casted, so it will not be countered by Dovescape. In most of cases, you cast Enduring Ideal you win the game because you can use it to find Humility first, Dovescape second and Night of Souls’ Betrayal third which form the combo. Then you can just find an enchantment that can turn into a creature and win the game.
This is a really good combo which only need one card (Enduring Ideal). But in the other hand, you need to wait three turns to find all of three enchantments, during which your opponent may destroy one of the enchantment and thus beat you down (note you can’t cast any spells after you cast Enduring Ideal).