Both Ibn Al Qayyim and Abul Qasim Al Qushayri made the comparison of Hope and Fear to two wings on a bird…
Maulana Jalalul Din Rumi said in his Mathnawi:
Hardship may dishearten at first,
but every hardship passes away.
All despair is followed by hope;
all darkness is followed by sunshine.
Ibn Rajab Al Hanbali (Allah have mercy on him) stated in his Istinshaq:
It is known that worship is built from only three sources: Fear, Hope, and Love. Each one is an intrinsic duty, and combining the three is an obligatory injunction.
Because of this, the Forbears censured whoever devoted oneself to one while neglecting the other two. [After all,] the innovation of the Khawarij and those resembling them came about from emphasizing fear while avoiding love and hope; the innovation of the Murji’a [those who believe that Iman guarantees the unrepentant safety from punishment for grave sins] came about from clinging to hope alone while avoiding fear; and the innovation of many advocates of freethinking and divine indwelling who ascribe themselves to devotion came about from singling out love while avoiding fear and hope.
Translated by Sidi Musa Furber.