What does « To besiege / To restrict » mean in the Quran?

And complete the Hajj and 'umrah for Allah. But if you are prevented, then [offer] what can be obtained with ease of sacrificial animals. And do not shave your heads until the sacrificial animal has reached its place of slaughter. And whoever among you is ill or has an ailment of the head [making shaving necessary must offer] a ransom of fasting [three days] or charity or sacrifice. And when you are secure, then whoever performs 'umrah [during the Hajj months] followed by Hajj [offers] what can be obtained with ease of sacrificial animals. And whoever cannot find [or afford such an animal] - then a fast of three days during Hajj and of seven when you have returned [home]. Those are ten complete [days]. This is for those whose family is not in the area of al-Masjid al-Haram. And fear Allah and know that Allah is severe in penalty.

[Charity is] for the poor who have been restricted for the cause of Allah, unable to move about in the land. An ignorant [person] would think them self-sufficient because of their restraint, but you will know them by their [characteristic] sign. They do not ask people persistently [or at all]. And whatever you spend of good - indeed, Allah is Knowing of it.

So the angels called him while he was standing in prayer in the chamber, "Indeed, Allah gives you good tidings of John, confirming a word from Allah and [who will be] honorable, abstaining [from women], and a prophet from among the righteous."

Except for those who take refuge with a people between yourselves and whom is a treaty or those who come to you, their hearts strained at [the prospect of] fighting you or fighting their own people. And if Allah had willed, He could have given them power over you, and they would have fought you. So if they remove themselves from you and do not fight you and offer you peace, then Allah has not made for you a cause [for fighting] against them.

And when the sacred months have passed, then kill the polytheists wherever you find them and capture them and besiege them and sit in wait for them at every place of ambush. But if they should repent, establish prayer, and give zakah, let them [go] on their way. Indeed, Allah is Forgiving and Merciful.