Brown-Driver-Briggs
מָחָר52 noun masculine, used often as
adverb, tomorrow, in time to come (Aramaic מְחַר ; probably properly time in front, Köii. 263, compare √, and Assyrian ma—ru, front, often of time, though always of former time, of old, DlHWB 402); —
1 to-morrow (the day following the present day),
a. as substantive Exodus 16:23 מָחָר ׳שַׁבָּתוֺן שַׁבַּת קֹדֶשׁ לְי to-morrow is a sabbath, etc., 1 Samuel 20:5 חֹדֶשׁ מָחָר to-morrow is the new moon, 1 Samuel 20:18; in יוֺם מָחָר Genesis 30:33; Proverbs 27:1; Isaiah 56:12; in the idiomatic phrase כָּעֵת מָחָר at the like of the time, (being) to-morrow, = about to-morrow (see כְּ 1a) Exodus 9:18; 1 Samuel 9:16; 1 Samuel 20:12; 1 Kings 19:2; 1 Kings 20:6; 2 Kings 7:1,18; 2 Kings 10:6; and in לְמָחָר Exodus 8:19 לְמָחָר יִהְיֶה הָאֹת הַזֶּה, = for, against, to-morrow, Exodus 8:6; Numbers 11:18; Joshua 7:13; Esther 5:12.
b. as adverb accusative Exodus 8:25; Exodus 9:5 מָחָר יַעֲשֶׂה הַדָּבָר הַזֶּה ׳י, Exodus 10:4 הִנְנִי מֵבִיא מָחָר אַרְבֶּה, Exodus 17:9; Exodus 32:5; Numbers 14:25; 1 Samuel 11:9 etc., Joshua 11:6 מָחָר כָּעֵת הַזּאֹת; opposed to הַיּוֺם Exodus 19:10 הַיּוֺם וּמָחָר, Joshua 22:18; 2 Samuel 11:12a; rhetorically, Isaiah 22:13 כִּי מָחָר נָמוּת.
2 = in future time, Exodus 13:14 כִּי יִשְׁאָֽלְךָ בִנְךָ מָחָר לֵאמֹר = Deuteronomy 6:20; Joshua 4:6,21; Joshua 22:24,27,28; so בְּיוֺם מָחָר Genesis 30:33.