The Ulam was an antechamber to the Heichal. The other doors and gateways of the Beis Hamikdosh were 20 Amos tall and10 Amos wide (approximately 10x5 metres). The great doorway of the Ulam was double, standing 40 Amos tall and 20 Amos wide!
All of the other doorways had doors which would be closed. Due to its sheer size, there was no door in the entrance of the Ulam. The doorway was always open, with only a massive curtain to give privacy.
The point of a needle is infinitesimally small. In spiritual growth, if we make even the tiniest opening through our own efforts, Hashem will help us in an incomparably expansive measure. This gateway is always open. All we need to do is take the first smallest of steps.
Like the opening of the Ulam, Hashem’s assistance and His blessings of success will not only be expansive, but will flow directly to us, with no doors to stand in their way.