Tafsir of Muhammad 47:19

"So know that there is no..." Having mentioned the state of the believers and the state of the disbelievers, He says: Once you know that the matter is as described—regarding the happiness of the former and the wretchedness of the latter—then remain steadfast in what you possess of knowledge regarding the Oneness of God, and in humility and self-abasement, by seeking forgiveness for your sin and the sins of those who share your faith.

"And God knows your fluctuations and your resting place." God knows your states, your activities, and your movements in your livelihoods and your trades. He knows where you reside in your homes, your movements throughout your life, and your final resting place in the graves. Or, it refers to your movements in your deeds and your final destination in Paradise or Hell. One such as this is worthy of being feared and revered, and worthy of having forgiveness and mercy sought from Him.

Regarding the priority of knowledge: Sufyan ibn ‘Uyaynah was asked about the virtue of knowledge, and he replied: "Have you not heard His words when He began with it? He said: 'So know that there is no god but God, and ask forgiveness for your sin' (47:19), commanding action after knowledge. He also said: 'Know that the life of this world is but play and amusement' (57:20), up to His saying: 'Race toward forgiveness from your Lord' (57:21). He said: 'And know that your properties and your children are but a trial' (8:28), then said afterward: 'So beware of them' (64:14). And He said: 'And know that anything you obtain of war booty, then indeed, for God is one-fifth of it' (8:41), then commanded action thereafter."