וַיִּתְפַּלֵּ֨ל אֶל־יְהוָ֜ה וַיֹּאמַ֗ר אָנָּ֤ה יְהוָה֙ הֲלוֹא־זֶ֣ה דְבָרִ֗י עַד־הֱיוֹתִי֙ עַל־אַדְמָתִ֔י עַל־כֵּ֥ן קִדַּ֖מְתִּי לִבְרֹ֣חַ תַּרְשִׁ֑ישָׁה כִּ֣י יָדַ֗עְתִּי כִּ֤י אַתָּה֙ אֵֽל־חַנּ֣וּן וְרַח֔וּם אֶ֤רֶךְ אַפַּ֙יִם֙ וְרַב־חֶ֔סֶד וְנִחָ֖ם עַל־הָרָעָֽה׃
Rashi on Jonah
was this not my contention—I know that, if they repent, You will not destroy them, and I will appear to them as a liar.
Malbim on Jonah
...I knew that even if they continued to worship idols that You would not destroy them, and that is why I did not want to go on this mission.