43 Grk “Now it happened that in.” The introductory phrase ἐγένετο (egeneto, “it happened that”), common in Luke (69 times) and Acts (54 times), is redundant in contemporary English and has not been translated.
44 Grk “he”; the referent (Jesus) has been specified in the translation for clarity.
45 Or “to a mountain” (εἰς τὸ ὅρος, eis to horos). The expression to the mountain here may be idiomatic or generic, much like the English “he went to the hospital” (cf. 15:29), or even intentionally reminiscent of Exod 24:12 (), since the genre of the Sermon on the Mount seems to be that of a new Moses giving a new law.
46 This is the only time all night prayer is mentioned in the NT.
47 This is an objective genitive, so prayer “to God.”

In other versions

In these days he went out to the mountain to pray, and all night he continued in prayer to God.

One of those days Jesus went out to a mountainside to pray, and spent the night praying to God.

During those days he went out to the mountain to pray and spent all night in prayer to God.

One day soon afterward Jesus went up on a mountain to pray, and he prayed to God all night.

Now it happened that in these days he went away to the mountain to pray, and was spending the whole night in prayer to God.

And it came to pass in those days, that he went out into a mountain to pray, and continued all night in prayer to God.

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