“Now during those days,
Jesus went out
To the mountain
He spent the night
Ἐγένετο δὲ ἐν ταῖς ἡμέραις ταύταις ἐξελθεῖν αὐτὸν εἰς τὸ ὄρος προσεύξασθαι, καὶ ἦν διανυκτερεύων ἐν τῇ προσευχῇ τοῦ Θεοῦ.
Luke said that during those days (Ἐγένετο δὲ ἐν ταῖς ἡμέραις ταύταις), Jesus went out to the mountain to pray (ἐξελθεῖν αὐτὸν εἰς τὸ ὄρος προσεύξασθαι). He spent the night (καὶ ἦν διανυκτερεύων) in prayer to God (ἐν τῇ προσευχῇ τοῦ Θεοῦ). Mark, chapter 3:13, also said that Jesus went up a mountain, much like Moses. Going to a mountain was a way of getting closer to God in the high heavens. Here Luke emphasized the prayerful solitary preparation of Jesus before his decision about the 12 apostles, as he spent the night praying to God. This also brings up the separation between Jesus and God,the Father.