ק֛וּם לֵ֥ךְ אֶל־נִֽינְוֵ֖ה הָעִ֣יר הַגְּדוֹלָ֑ה וִּקְרָ֤א אֵלֶ֙יהָ֙ אֶת־הַקְּרִיאָ֔ה אֲשֶׁ֥ר אָנֹכִ֖י דֹּבֵ֥ר אֵלֶֽיךָ׃
“Bangunlah, pergilah ke Niniwe, kota besar itu, dan serukanlah kepadanya seruan yang Aku sampaikan kepadamu.”
Ibn Ezra
"Get up"- He [God] is showing him [Yonah] that he did not go a way that distanced him from Nineveh [since the fish spat him out on the shore of Nineveh], [therefore] if He sends him a second time, he will go.
Metzudat David
what I tell you: and that is what Jonah later said, that in forty days Nineveh would be overturned. It wasn't necessary to spell that out here, because it is obvious.
Malbim
Why did God change this time to say, "and proclaim to it what I tell you", unlike what God said the first time?