Kabbalisticlly the seventh represents the level of malchus, like the womb that takes the seed and actualizes – to begin is the seed, the supernal-wisdom, Chohmah; but the goal of an idea of-course is the fruit – so the Rebbe, being the seventh generation, represents the completion of Divine instructions and his behavior, the ultimate example of it actualized – and if we had to sum the Rebbe, it was the creed and deed – DO and never limit how much!