Can You Walk in Front of One Who Is Praying?
Question

I was praying Maghrib and a rabbit passed in front of me. Is my prayer interrupted because of that?
Praise be to Allah.What does not interrupt prayer?
Shaykh `Abd Al-`Aziz ibn Baz (may Allah have mercy on him) said:
If a rabbit or any other animal walks in front of the person who is praying, it does not interrupt the prayer. Rabbits, goats and other animals do not interrupt the prayer.
The three entities that interrupt prayer
Rather the prayer is only interrupted by three things according to the correct scholarly opinion: an adult woman, a black dog and a donkey.
This is what is narrated from the Prophet (blessings and peace of Allah be upon him), that he said: “Three things interrupt a man’s prayer [by passing in front of him] if he does not have in front of him something the height of the back of a saddle: a woman, a donkey and a black dog.” It was said: O Messenger of Allah, why black and not red or yellow? He said: “The black dog is a devil.”
What is meant is that these three are the things that interrupt the prayer according to the correct scholarly opinion.
There is some difference of opinion among the scholars, but the correct view is that prayer is only interrupted by one of these three things, either a woman, or a donkey in general, or a black dog specifically. As for other kinds of animals, such as dogs that are not black, or camels, goats, rabbits, cats and so on, none of these interrupt the prayer. But if it is possible not to let them walk in front, and the worshipper tries not to let them pass in front of him that is better. So he should not let anything pass in front of him.
Can you walk in front of one who is praying?
Similarly, if a man walks in front of the worshipper it does not interrupt his prayer, but it detracts from its reward, so he should prevent anyone walking in front of him if possible. It is not permissible to walk in front of the worshipper.
The Prophet (blessings and peace of Allah be upon him) forbade that and said: “If the one who walks in front of a person who is praying knows (the sin) that is upon him, standing for forty would be better for him than passing in front of someone who is praying.”
And he enjoined the one who is praying facing something to screen him from the people not to let anyone walk in front of him; rather he should stop him. He (blessings and peace of Allah be upon him) said: “If one of you prays facing something to screen him from the people, if someone wants to walk in front of him, let him push him away, and if he insists then let him fight him, for he is no more than a devil.”
Preventing interruptions during prayer
The Sunnah indicates that the one who is praying should prevent anything or  anyone who wants to pass in front of him even if they are not one of those three, neither a dog nor a woman nor a donkey. He should not let anything pass in front of him, whether it is a human being or an animal, if it is possible for him to prevent that. But if it overcomes him and passes in front of him, it does not affect his prayer. His prayer is affected and interrupted by one of the three: a black dog or a woman or a donkey. These three interrupt the prayer because of the saheeh hadeeth quoted previously.
Role of Sutrah in maintaining focus
The Sunnah is for the believer who wants to pray to put something in front of him, such as a chair or a spear that he sticks in the ground, or a wall or pillar that he faces towards when he is praying so that nothing will pass in front of him that could interrupt his prayer.
If people are passing beyond his Sutrah (screen), that does not affect his prayer. But if they pass in front of him and between him and the Sutrah, this is what is not allowed. If the one that passes in front of him is a woman or a donkey or a black dog, his prayer is interrupted.
If he has a Sutrah and they pass in front of him close to him, this is not allowed. If he does not have a Sutrah and they pass close to him, within three cubits or less, then that interrupts his prayer, but if they pass far away, then that does not matter.
If they pass in front of him, more than three cubits away, that does not matter, because the Prophet (blessings and peace of Allah be upon him) prayed inside the Ka`bah, leaving three cubits between him and the western wall.
Distance and placement of Sutrah
The scholars quoted this as evidence that this is the maximum distance at which the Sutrah should be placed; the Sutrah should be three cubits away or less. If the thing passes further away than that, its passing (in front of the worshipper) does not affect his prayer.
If there is a Sutrah, whatever passes beyond it does not matter. What is meant by interrupting the prayer, as mentioned here, is rendering it invalid.
Consequences of interruption of prayer
The majority of scholars say that his prayer is interrupted in the sense of being rendered imperfect, but the correct view is that it is interrupted in the sense that he has to repeat it. So if it is an obligatory prayer then he has to repeat it. So he has to repeat it if one of these three passes in front of the worshipper between him and his Sutrah, he has to repeat the prayer.”