Dawood, you asked what the previous verses had to do with verse 9, so here is Surah 62 in context:
Surah 62. Al-Jumu'ah – The Congregation
[Author’s Note] This is the 62nd Surah of the Qur’an and it has 11 verses. This Surah emphasizes that the Book of God must be understood and acted upon. Merely reciting or showing reverence is not enough. Friday must not be equated with Sabbath since we find in 62:10 That Muslims are expected to work seeking God’s bounty on this day as on other days of the week.
With the Glorious Name of God, the Instant and Sustaining Source of all Mercy and Kindness
62:1 All that is in the heavens and all that is on earth strive to manifest the glory of God, the King Supreme, the Impeccable, the Almighty, the Wise.
Everything does what God has programmed them to do.
62:2 He is the One Who has sent a Messenger among the unlettered ones to convey to them His messages, to make them grow in humanity, to teach them the Law and the wisdom behind it. Whereas before that they were obviously lost in error,
[Ummi = Gentile = Non-Israelite = Unlettered. Zaku, Tazkiah = Growth = Purity from vice = Development of the ‘self’ = Self-actualization. Hikmah = Wisdom = Judgment = Governance]
God has now sent our programming to us, His message via the Messenger.
62:3 Along with others who have not yet joined them (in time and place). He is Mighty, Wise.
62:4 Such is God’s bounty – which He bestows upon him who is willing to receive it. (His light is available to whoever turns it on.) God is the Lord of the magnificent bounty.
Anyone who followed and will follow this will benefit from following God.
62:5 (The Book of God is to be read and understood, and not placed in high niches.) The example of those who were entrusted with Torah, and did not apply it in their daily lives, is that of the donkey that carries a load of books. Evil is the example of people who deny God’s revelations by their misdeeds. God does not guide people who choose to do wrong (and displace the revelation from its rightful status).
[Kizb = Belie = Give lie = Deny in practice. Kufr = Reject openly = Darkness = Denial = Ingratitude = Concealing. Zulm = Dislodge from the rightful place = Relegate the truth = Give preference to conjecture = Oppression = Wrongdoing = Violation of human rights]
Previous peoples were given the same message and ignored it.
62:6 Say, “O You who are Jewish! If you claim that you are friends to God to the exclusion of the rest of mankind, then long for death if you are truthful!” (And hope to meet with your Lord for eternal bliss.)
62:7 But they will never long for it because of what their hands have sent ahead. God is fully Aware of the wrongdoers. [2:94-96. See Zulm, 62:5]
62:8 Say, “The death which you fear so much is bound to overtake you, and then you will be returned to the Knower of the Invisible and Visible. Then He will make you understand what you used to do.”
When they were invited to follow the Message they denied it, they made no attempt to put it into practice. They claimed to follow God's teachings, promised themselves paradise to the exclusion of all others, but lacked character so "feared death".
62:9 O You who have chosen to be graced with belief! When the call for Salaat (carrying out Divine commands) is announced on the Day of the Congregation, hasten to the remembrance of God and leave your commerce. That is for your own good if you use your knowledge to understand.
62:10 And when the Salaat has been completed, disperse freely in the land and seek God’s bounty and remember God (and His commands) often so that you may prosper. [62:4]
Those who now follow the Message, when called at anytime, come together to put the teachings of God into practice, so that everything they do is from the Quran, closely following, being dutiful to this.
62:11 Yet when they see some bargain or entertainment, they rush to it, and leave you standing. Say, “What is with God is better than all entertainment and all bargain. God is the Best of providers.”
There are those who were whistling and clapping in their religious acts, and even when the new Guidance has come, they leave this and continue in their ritualised prayers, when there are no instructions in the Quran, the only revelation we are asked to follow, but this is not enough for them.