In Zohar Parshas Yisro, the Aseres HaDibros (Ten Commandments) are discussed at length, as that was when the Torah was given at Har Sinai. An interesting statement there is that the entire Torah is included in these specific mitzvos, and one who contemplates them can merit wonderful levels in understanding and general spiritual growth.
The prohibition against taking a false oath on Hashem’s name is discussed. The essential question is, “Why is this such a severe prohibition?” The Zohar explains that this is such a severe prohibition because when Hashem made the world, He created a place deep in the Tehom (Depths) where He put a “shard” that He engraved His Name Havayah on, and every oath made descends to this place and the shard receives it. When a true oath is made, Hashem’s name is exalted through this and His name is “strengthened,” like an engraving on clay or wax that is deepened with a stylus. The opposite is true though, rachmono litzlon, when someone swears falsely, that it is like the Shem is erased and weakened, and the world is brought close to destruction through swearing a false oath; until Hashem calls a specific Malach to go and fix the name upon the shard.
There’s an idea in Chassidus that I heard once, the source escapes me, that when a person makes an oath in Hashem’s name the entire Creation comes forward to assist in the fulfillment of this oath. This is one aspect of the idea in halacha that one who needs to do t’shuva may make such a serious oath in regards to this particular effort, since all Hashem’s Creation will come to help him do this he will then be able to accomplish that which he seeks to do. This is an aspect of what it says much earlier in the Zohar HaKodosh as well, that the Yetzer HaRa can be made a helper to one rather than an enemy. There’s a segulah brought by Rebbe Nachman that making an oath and fulfilling it immediately brings one to oneg Shabbos (enjoyment of Shabbos).
The main thing that ties these all together is the idea of exalting Hashem’s name. It’s brought in various places that through t’shuva Hashem’s name is exalted; much the same as testifying to His creation of the world on Shabbos through delighting in Shabbos exalts His name. It is of the utmost importance that we fulfill any vows we take, and make them when necessary. Though there are many warnings about this, and they are to be certainly taken seriously, sometimes an oath intended to be kept with complete sincerity is just the thing needed to tip the scales of our personal merits to attain true t’shuva and Geulah Yechidis (personal redemption), as well as what we all need to attain the Geulah Shleimah (complete redemption).