This story is originally found in The Holy Injil, in the book of Luke, Surah 24 Ayat 50 through 53. Included below is the original text in Greek, followed by a modern English translation.
50 Ἐξήγαγεν δὲ αὐτοὺς ἕως πρὸς Βηθανίαν, καὶ ἐπάρας τὰς χεῖρας αὐτοῦ εὐλόγησεν αὐτούς. 51 καὶ ἐγένετο ἐν τῷ εὐλογεῖν αὐτὸν αὐτοὺς διέστη ἀπ’ αὐτῶν καὶ ἀνεφέρετο εἰς τὸν οὐρανόν ]⸃. 52 καὶ αὐτοὶ προσκυνήσαντες αὐτὸν ]⸃ ὑπέστρεψαν εἰς Ἰερουσαλὴμ μετὰ χαρᾶς μεγάλης, 53 καὶ ἦσαν διὰ παντὸς ἐν τῷ ἱερῷ εὐλογοῦντες τὸν θεόν.
50 Then Isa led them to Bethany. And lifting up his hands, he blessed them. 51 While he was blessing them, he departed from them and was taken up into heaven. 52 They worshiped him, and then returned to al-Quds with great joy. 53 And they spent all of their time in the temple, praising Allah.