Four sevens are 28, and from the time when the first Han emperor Liu Bang destroyed the Qin, to when Liu Xiu raised his army, was exactly 228 years, and this seemed to fit in with the prophecy.
四乘七是廿八，從漢高祖劉邦滅秦到劉秀起兵時正好時隔兩百廿八年，似乎呼應了讖文的預測。