Some people are soft on the outside and tough inside and some the opposite. All soft or all tough is immature. Maturity is interinclusion.
Yosef Yitzchak, the 6th Lubavitcher Rebbe was of the first category (soft outside tough inside), Menachem Mendel, the 7th, of the second.
Yosef Yitzchak plus Menachem Mendel = Samson, who was tough outside (like Menachem Mendel) and inside (like Yosef Yitzchak), but immature.
The rectified/mature union of Yosef Yitzchak and Menachem Mendel (a messianic union) is to be both soft and tough, both outside and inside.