Chapter: At the beginning of Islam, intercourse did not necessitate ghusl unless semen was emitted, then that was abrogated and ghusl becomes obligatory for intercourse
Abu al. 'Ala' b. al-Shikhkhir said:
The Messenger of Allah (ﷺ) abrogated some of his commands by others, just as the Qur'an abrogates some part with the other. - Sahih:Muslim:344 (islam)

-How can we know what is abrogated?

There shall be no compulsion in [acceptance of] the religion. The right course has become clear from the wrong. So whoever disbelieves in Taghut and believes in Allah has grasped the most trustworthy handhold with no break in it. And Allah is Hearing and Knowing. - Quran:Al-Baqarah 2:256 (islam)

-Does it mean Islam is true and everybody can see it?
- Does it mean the atheist are liars?
- Is it the reason for violence against unbelievers?
- Is there another verse more foundational for Religious Violence?
- Is this verse abrogated by 9:5?

[4]Nor will I be a worshipper of what you worship.
[5]Nor will you be worshippers of what I worship.
[6]For you is your religion, and for me is my religion." - Quran:Al-Kafirun 109:4:6 (islam)

-Is it a clear command for all Muslim to disregard earthly rules if they contradict the Divine Law?
- Is it possible for a Muslim to respect an apostate, to respect a woman who don't want the veil?

We do not abrogate a verse or cause it to be forgotten except that We bring forth [one] better than it or similar to it. Do you not know that Allah is over all things competent? - Quran:Al-Baqarah 2:106 (islam)

-Why abrogation, is Allah omniscient?
- Was it for the Quran or for other revelations?