Matthew 12:38-40 English Standard Version (ESV)
The Sign of Jonah
38 Then some of the scribes and Pharisees answered him, saying, “Teacher, we wish to see a sign from you.” 39 But he answered them, “An evil and adulterous generation seeks for a sign, but no sign will be given to it except the sign of the prophet Jonah. 40 For just as Jonah was three days and three nights in the belly of the great fish, so will the Son of Man be three days and three nights in the heart of the earth.
Mattityahu 12:38-40 Orthodox Jewish Bible (OJB)
38 Then some of the Sofrim and Perushim answered Rebbe, Melech HaMoshiach, saying, Rabbi, we desire to see an ot (miraculous sign) from you.
39 But Rebbe, Melech HaMoshiach answered them, Dor rah umnaef (an evil and adulterous generation) seeks for an ot (miraculous sign), but no ot will be given it except the ot of Yonah HaNavi.
40 For just as Yonah was in the belly of the great fish SHLOSHAH YAMIM USHLOSHAH LAILAH (three days and three nights, YONAH 1:17), so will be the Ben HaAdam (Moshiach) in the heart of the earth SHLOSHAH YAMIM USHLOSHAH LAILOT (three days and three nights).