God has intellect. He is omniscient (i.e., all-knowing). His ability to know and understand is without limit.
- And there is no creature hidden from His sight, but all things are open and laid bare to the eyes of Him... - Hebrews 4:13
- Great is our Lord and abundant in strength; His understanding is infinite. - Psalm 147:5
He has complete knowledge of all things.
- For truly my words are not false; One who is perfect (tāmîm) in knowledge is with you. - Job 36:4
The term perfect (tāmîm) means that God’s knowledgde is complete or lacking in nothing. As well, God knows the end from the beginning.
- Declaring the end from the beginning, And from ancient times things which have not been done, Saying, My purpose will be established, And I will accomplish all My good pleasure; - Isaiah 46:10
He knows every detail of every person’s life, understands a person’s thoughts and scrutinizes a person’s actions.
- You know when I sit down and when I rise up; You understand my thought from afar. You scrutinize my path and my lying down, And are intimately acquainted with all my ways. Even before there is a word on my tongue, Behold, O Lord, You know it all. - Psalm 139:2-4
He knows what is done in secret.
- so that your fasting will not be noticed by men, but by your Father who is in secret; and your Father who sees what is done in secret will reward you. - Matthew 6:18