Imam Al Bukhari said in Juz Raful Yadayn:
“Whoever claims that raising the hands (in prayer) is an innovation, then he has defamed/challenged (طعن) the companions of the prophet , and the Salaf and those who came after them, and the people of Hijaaz, the people of Madeenah, the people of Makkah and a number from the people of Iraaq and the people of Ash Shaam, the people of Yemen and the scholars of Khurasaan.
Majid Jawed Al Afghanee

Shaykh Bakr Abu Zayd rahimahullah said:

One of the new things that we see some people doing, with no evidence in sharee’ah, is that in prayer they try to align themselves with a person on the right if they are on the right hand side of the row, or to align themselves with a person on their left if they are on the left hand side of the row, and they turn their feet inward so that their ankles are touching the ankles of the people next to them.

This is something for which there is no basis in sharee’ah and it is going to the extreme in implementing the Sunnah. This is wrong on two counts.

The alignment of the row should begin from where the imam is standing. Whoever is on the right of the row should align himself by looking at those who are to his left (i.e., closer to the imam). Thus the line will be straightened and the gaps will be filled. Alignment is done by lining up necks, shoulders and ankles, and by completing the front rows.

But to try to spread the legs wide and turn the feet inward so that one’s ankles touch one’s neighbours’ ankles is an obvious mistake and an exaggeration, and a new interpretation which is indicative of going to extremes in trying to apply the Sunnah. It causes annoyance and is not prescribed in sharee’ah, and it widens the gaps between people standing in prayer.

That becomes apparent when the people prostrate, and when they stand up again they become distracted in trying to fill the gaps and turning their feet to make their ankles touch their neighbours’ ankles, which makes them miss out on what they should be doing, which is to make the toes point in the direction of the qiblah.

Doing that is like competing with one’s neighbour and trying to take his place. All of that is not prescribed in sharee’ah.

Laa jadeed fi Ahkaam al-Salaah, 12. 13.

Abu Sa`id said, “I heard the Prophet (ﷺ) saying, ‘If anybody amongst you is praying behind something as a Sutra and somebody tries to pass in front of him, then he should repulse him and if he refuses, he should use force against him for he is a Shaitan (a Satan).’ ”
Shaykh Al Bassam mentioned in Tawdeehul Ahkaam 2/83
“This narration is proof upon the greatness of the sin of the one who passes (in front of the one praying) and his crime, until some of the scholars and from them Ibnul Qaiyum considered it from the Major Sins”

The noble scholar alfawzan:
The sheikh, the scholar, Salih Al-fawzan- may Allah preserve him:
“If a man prays with his wife at home she stands next to him. If she is a foreign women (non-mahram) than behind him”
Reference: Aghatha Al-lahfan – Jumada-Al-Awwal 26 1437

If Someone Sits to be a Sutrah for Another Person, Will He be Rewarded? – Shaikh Abdul-Muhsin al-‘Abbad
Question: Some of the brothers make themselves a sutrah for the one who came late to the prayer. In terms that they sit in front of him believing that there is reward in that. So what is the ruling on it?
Answer: “As for him being a sutrah, then there is no problem in that. As for the one sitting as a sutrah, whether he will have a reward or not? He will have a reward because he is doing good to him [the one praying]. And Allah knows best. Yes. Verily Actions depend on intentions”.
[Sharh Ibn Majah no. 74]
Translated by
Faisal Ibn Abdul Qaadir Ibn Hassan

Abu Sulaymaan

Ibn Umar said:
I asked Bilal: How did you find the Messenger of Allah (ﷺ) responding to them when they gave him a salutation while he was engaged in prayer. He replied: In this way, and he spread his Palm.
Shaykh Al Bassam said:
The obligation of returning the Salam, due to Allah Ta’ala statement:
و اذا حييتم بتحية فحيوا باحسن منها او رُدُّوهَا 
86. When you are greeted with a greeting, greet in return with what is better than it, or (at least) return it equally. 
The indication for the one praying is the best which he is capable upon in regards to returning the Salaam.
Tawdeehul Ahkaam 2/58 
Note The Narration Shaykh Albani authenticated it
Majid Jawed al Afghanee

Narrated Jabir bin `Abdullah:
Allah’s Messenger (ﷺ) said, “Whoever after listening to the Adhan says, ‘Allahumma Rabba hadhihi-dda` watit-tammah, was-salatil qa’imah, ati Muhammadan al-wasilata wal-fadilah, wa b`ath-hu maqaman mahmudan-il-ladhi wa`adtahu’ [O Allah! Lord of this perfect call (perfect by not ascribing partners to You) and of the regular prayer which is going to be established, give Muhammad the right of intercession and illustriousness, and resurrect him to the best and the highest place in Paradise that You promised him (of)], then my intercession for him will be allowed on the Day of Resurrection”.
The Dua in Arabic is:
اللَّهُمَّ رَبَّ هَذِهِ الدَّعْوَةِ التَّامَّةِ وَالصَّلاَةِ الْقَائِمَةِ آتِ مُحَمَّدًا الْوَسِيلَةَ وَالْفَضِيلَةَ وَابْعَثْهُ مَقَامًا مَحْمُودًا الَّذِي وَعَدْتَهُ، حَلَّتْ لَهُ شَفَاعَتِي يَوْمَ الْقِيَامَةِ
Shaykh Al Bassam mentioned in Tawdeehul Ahkaam Volume 1 Page 622 
That the following additions to this dua are weak and not authentic 
 1. اللهم اني اسالك بحق هذه الدعوة
2. و الدرجة الرفيعة
3. انك لا تخلف الميعاد 
4. يا ارحم الراحمين 
Majid Jawed Al Afghaanee

Shaykh Al Uthaymeen said:
It is befitting that the preference be given to the one with a good voice in regards to the Athaan, and a good voice is with three matters:

Good presentation, good tone, and strong voice 
If these three are gathered in a Muathin then it is the most complete that can be.
Explanation of Bulughul Maraam 2/97 
Majid Jawed Al Afghaanee