The first Hebrew letter - Aleph - represents the unification of opposites. At the end of the Passover Seder there is the song, ‘Who Knows One?’ The answer, ‘I know One, One is our God who is in the Heavens and the Earth’. This means that God can be found both outside of ourselves (in the Heavens) and inside of ourselves (and the Earth).
The shape of this letter Aleph is comprised of an upper red part (actually a Hebrew letter Yod) representing Heaven; a lower part blue part (an upside-down Yod) representing Earth; balanced by a yellow diagonal part (actually a Hebrew letter Vav - pronounced Wow - which means ‘and’).
The diagonal Wow represents a constant balancing and uniting of the two opposite forces represented by the two Yods. It can also be seen as the numeral 1. The two are united into One by the Wow. The number value of the three Hebrew letters Yod Wow Yod is 26, the same gematria as the four Hebrew letters of the Holy Name YHWH.
And as we say, 'God is One', the numerical value of the first Hebrew letter, Aleph, is One.