Throughout the Scriptures, God has communicated through numbers which are both literal counts as well as symbolic numerics. In fact, the message is often as much, or more, within the symbolism of the numbers as it is within the words. Symbolic numbers, like golden threads within a garment, run all through the scriptures. But they are especially apparent in the books of Daniel, the Gospel of John, and book of The Revelation. To ignore these symbolic associations often loses or confuses the intended significance of a text. For example, most readers would associate the number twelve (12) with things being for the people-of-Israel through the existence of twelve tribes, but miss the fact that the woman healed after touching Jesus’ garment hem had been ill for twelve (note the 12) years (Matt.9:20), and that the girl raised from the dead was twelve years old (Mark 5:22, 41). Jesus came with healing for the people-of-the-promise as indicated by those included numerics. Later, those who followed Him were led by the twelve apostles, i.e. those twelve leaders were given for the people of the promise in the new age. That age also began with 120 individuals in the upper room, and that used both the numerics 12 and 10, (Acts 1:15).
The numeric 43 is related to things, or people, being 'out-of-place', being 'not as they were intended', or indicating the condition of being 'not where one is supposed to be'.
When Joseph died, the Israelites were supposed to take his body back to Canaan for burial near the tombs of Jacob and Abraham (Gen.50; Gal.3:17). But they didn't. His death therefore began a 430 year "sojourn" in Egypt. The Israelites stayed in Egypt, but they were not where they were supposed to be (Gen.50:25).
The sojourn of 430 years (or 43 times 10) is compatible with the numeric 43 of being 'out of place' and the '10' of being a 'complete' within the 'world' (Ex.12:40, 41). Those 430 years became 30 (a numeric of 'waiting') years under Ephraim, followed by 400 (a numeric of 'endurance') years when the Israelites were servants to the new rulers over Egypt (Gen.15:13; Act.7:3). The Israelites finally took Joseph's bones back to Canaan at the time of the exodus (Ex.13:19).
Many writers have attempted to associate a symbolic meaning with Abraham's 318 servants in Gen.14:14. Unfortunately, the numeric 318 has usually been misinterpreted. That's because the true number to be observed is 322, or even larger if the Amorites brought soldiers. The band that was victorious over those kings who had harmed Abraham's family numbered at least 322. In addition to the 318 servants, there was Abraham himself and three Amorites which made a total of 322. [Gen.14:24] The numeric '322' is '23x2x7'. Factors of this numeric would seem to indicate it was within 'God's plan' (by '7'); and was to be 'a warning' (in '23') of the harm to come upon those who would come against Abraham or his family. [Gen.12:3]