Knowing Allāh subḥānah is of two types:
First, an awareness that leads to affirmation [of God’s existence], this [knowledge] is common amongst all people: the righteous, the evil; the obedient, the disobedient.
Second, an awareness that necessitates shyness from Him, love for Him, attaching the heart to Him, yearning to meet Him, fearing Him, turning to Him and repenting to Him, finding solace in Him, and fleeing from the creation to Him.
This is a special awareness that is known to a certain people. The level of discrepancy of this awareness amongst people cannot be fathomed except by the One who has made Himself known to them, and Who has made some hearts aware of Him in a way that He has concealed to others, and this awareness with each person is indicated by his status [with Allāh] and how much [Allāh] has revealed to him.
The most knowledgeable of creation ﷺ said about Him, ❝I do not count any praise for you, You are as You have praised Yourself.❞ He ﷺ also said that on the Day of Resurruction, Allāh the Almighty will reveal some words of praise [to the Prophet ﷺ] that he is unable to utter now.
The second type of awareness has two broad categories:
1. Thinking about and reflecting on all the Qurʾānic verses, and having a deep understanding of [the speech of] Allāh and of His Messenger ﷺ.
2. Thinking about His observable signs and reflecting on His Wisdom in them, [and reflecting on] His Power, His Gentleness, His Kindness and His Fairness, and [reflecting on how He] always maintains His creation with justice.
The sum of the two types of knowledge:
To be knowledgeable of the meanings of His Beautiful Names, their Majesty, their Perfection, His Uniqueness, and their connection with the creation and the orders of Allāh. The one who has this knowledge will then be an expert in understanding His Commands and Prohibitions, an expert in understanding His Decree and Destiny, an expert in understanding His Names and Attributes, an expert in understanding religious rules and the rules of this universe.
﴿ذَٰلِكَ فَضْلُ اللَّهِ يُؤْتِيهِ مَن يَشَاءُ ۚ وَاللَّهُ ذُو الْفَضْلِ الْعَظِيمِ﴾
﴾Such is the bounty of Allāh which He gives to whom He wills, and Allāh is the possessor of great bounty.﴿ Al-Ḥadīd:21
[Translated from the Ibn Qayyim’s (raḥimahu Allāh) book, al-Fawāid, p.209]