By the time of the beloved (Prophet).
By the time of the afternoon
And/by the time/era/end of day to dusk
Hereby God swears by time
By oath of this era of yours (O dear Prophet Mohammed – peace and blessings be upon him)
By the passing time (whose rotation bears witness to the affairs of mankind). Or By the Prayer of declining day (‘Asr, for this Prayer is the middle of all Prayers). Or By the declining time of the day, (when the sun, after shining for the whole day, presents the sight of its setting). Or By the holy era of the Prophethood of Muhammad (blessings and peace be upon him), the sole objective and the most coveted achievement of all ages historic as well as pre-historic, and of all times to come
I cite as witness the Time