Albert Barnes Commentary Jonah 4:7

"But God prepared a worm when the morning rose the next day, and it smote the gourd, that it withered." — Jonah 4:7 (ASV)

When the morning rose—that is, in the earliest dawn, before the actual sunrise. For one day Jonah enjoyed the refreshment of the castor oil plant. In early dawn, it still promised the shadow; just before it was most needed, at God’s command, it withered.