Our lives are streams flowing into the same river towards [the] heaven lies in the mist beyond the falls.
把whatever改成 the,然后与 1楼那句话 对比。
这the句指有个确定的heaven即the heaven, 且后面 lies...falls描述其特征。
Whatever句指无确定性的whatever heaven,但“无论哪种天堂”仍具有lies...falls属性。从而暗示发话人的观点:无论哪种天堂,或无论你如何称呼它,或...(要看前文),我都要陈述此事实(或观点,或论点)