Markus 13:33

13:33 Watch out! Stay alert! ¹  For you do not know when the time will come.

Markus 13:35

13:35 Stay alert, then, because you do not know when the owner of the house will return – whether during evening, at midnight, when the rooster crows, or at dawn –

[13:33]  ¹ tc The vast majority of witnesses (א A C L W Θ Ψ Ë^1,13 Ï lat sy co) have καὶ προσεύχεσθε after ἀγρυπνεῖτε (agrupneite kai proseucesqe, “stay alert and pray”). This may be a motivated reading, influenced by the similar command in Mark 14:38 where προσεύχεσθε is solidly attested, and more generally from the parallel in Luke 21:36 (though δέομαι [deomai, “ask”] is used there). As B. M. Metzger notes, it is a predictable variant that scribes would have been likely to produce independently of each other (TCGNT 95). The words are not found in B D 2427 a c {d} k. Although the external evidence for the shorter reading is slender, it probably better accounts for the longer reading than vice versa.