In every work of God there is something first, something intermediate, and something last; and what is first works through what is intermediate to what is last and in this way becomes manifest and persists, so what is last is a foundation. The first is also in the intermediate, and through the intermediate is in what is last, so what is last is a container; and since what is last is a container and a foundation, it is also a support.
The learned world understands that this series of three can be called the purpose, the means, and the result, as well as being, becoming, and achieving full manifestation. Being is the purpose, becoming is the means, and achieving full manifestation is the result. This means that there is a series of three in everything that is complete—a series called first, intermediate, and last; or purpose, means, and result; or being, becoming, and achieving full manifestation.
Once this is understood we can also understand that every work of God is complete and perfect in its final stage and also that the whole, which is a series of three, is in the final stage, because the prior stages are together in it.
This is why three in the Word spiritually understood means complete, perfect, and all together; and since this is its meaning it is used in the Word whenever anything is so described, as in the following instances:
Isaiah went naked and barefoot for three years (Isaiah 20:3). Jehovah called Samuel three times, Samuel ran to Eli three times, and the third time Eli understood what was happening (1 Samuel 3:1–8). David told Jonathan that he would hide in the field for three days; later Jonathan shot three arrows beside the rock; and after that David bowed down to Jonathan three times (1 Samuel 20:5, 12–41). Elijah stretched himself out on the widow’s son three times (1 Kings 17:21). Elijah ordered people to pour water over a burnt offering three times (1 Kings 18:34). Jesus said that the kingdom of the heavens was like yeast, which a woman took and hid in three measures [of flour] until it was all leavened (Matthew 13:33). Jesus said to Peter that Peter would deny him three times (Matthew 26:34). The Lord said to Peter three times, “Do you love me?” (John 21:15, 16, 17). Jonah was in the belly of the whale three days and three nights (Jonah 1:17). Jesus said that they would destroy the Temple, and he would build it in three days (Matthew 26:61). Jesus prayed three times in Gethsemane (Matthew 26:39–44). Jesus rose on the third day (Matthew 28:1).
There are many other passages where threes are mentioned, and they are mentioned when it is a matter of something finished and completed, because that is what this number means.
from Sacred Scripture White Horse, Sections 27-29