The key lays, it seems to me, in the massed appreciation by these generations of the spirituality of daily labor. It is through a conscious endeavor of linking in thought one's daily labors to the Hearts of many others that spiritual regeneration of the Planet and Human relations will occur. It is not the great conscious labor of the heart of a few, but the massed achievement and labor of the heart of many that creates the receptivity of the Mundane world of our daily existence to the "Supermundane" world of regenerating energies. Through a deeper appreciation of the heart as the link to the Planetary Heart by many comes the synchrony and synthesis of human aspirations for the Common Good. This is labor of and through the heart.
Essentially, it is the Will-to-Brotherhood of Humanity - the core quality of unified hearts.
"When any step of ascent is achieved in earthly life, without departing from one's daily routine, it can be called the highest test. True, it is difficult to hold one's torch high amidst crude vibrations, malice, and ignorance, but then the greater is the achievement. By maintaining a constant striving toward the Higher Worlds without turning away from daily life, that containment will be found which people call synthesis. But how rarely does one find in life the toilers who have dedicated themselves to the service of the Higher World!
"People sometimes talk about the Common Good, yet this goal will only be possible through the embracing of the Higher World. Only then will the process of perfectment become a wise one, and unite all quests of humanity. The varied paths of all pilgrims will then be accepted and understood. They all walk the one path, and only their words differ.
"The Thinker said to the disciples, 'Embrace all, understand, and love.'" Supermundane IV, 722.