וַיְהִי אַחַר הַדְּבָרִים הָאֵלֶּה וְהָאֱלֹקים נִסָּה אֶת אַבְרָהָם וַיֹּאמֶר אֵלָיו אַבְרָהָם וַיֹּאמֶר הִנֵּנִי
It happened after these events that G-d tested Abraham. He said to him, "Abraham," and he replied, "Here I am."
The akeidah – the story of the binding of Isaac – is read as part of the preliminary morning service. What does it mean that G-d tested Abraham. If G-d is omniscient (which He is), wouldn’t He already know what Abraham would do under given circumstances? The Ramban explains that a test is not for G-d’s benefit, it’s for the sake of the one being tested. A test takes a person’s innate potential righteousness and actualizes it. In this way, the person can be rewarded for his choices.