“There is a difference between theoretically knowing that God is always present and knowing it when one is crushed.
To be sure, there are many saints, and even ordinary men, who are able to bless the evil as well as the good, not only to receive it without complaint, but also to accept it with joy.
The capacity to do so is a function of deeper comprehension as well as of faith or certainty in the wisdom of the hidden workings of God.
Hence we understand the meaning of the verse: ‘“Happy is the man whom Thou, O God, chasteneth . . .’” (Psalms 94:12).”
-Rabbi Adin Steinsaltz
From Pebbles of Wisdom from Rabbi Adin Steinsaltz