Tomorrow in Scripture signifies time future, as Jacob in Genesis says, “Tomorrow shall my righteousness hear me.” [Gen 35:33] And in the phantasm of Samuel the Pythoness says to Saul, “Tomorrow shalt thou be with me.” [1 Sam 28:19]
He yields therefore unto them that they should care for things present, though He forbids them to take thought for things to come. For sufficient for us is the thought of time present; let us leave to God the future which is uncertain. And this is that He says, “The morrow shall be anxious for itself;” that is, it shall bring its own anxiety with it. “For sufficient for the day is the evil thereof.” By evil He means here not that which is contrary to virtue, but toil, and affliction, and the hardships of life.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).