Dealing with Waswasa in Prayers

Bismillahi Walhamdulillah

I have seen often people ask the questions related to Waswasas. In this thread I will try to address this issue.

First thing I want to say is that if you are having waswasa in your prayers & you are worried about them then congratulation because this is a clear clear sign of faith based on the following hadith of Prophet Muhammad (peace be upon him):

It is narrated on the authority of Abu Huraira that some people from amongst the Companions of the Apostle (ﷺ) came to him and said:

Verily we perceive in our minds that which every one of us considers it too grave to express. He (the Holy Prophet) said: Do you really perceive it? They said: Yes. Upon this he remarked: That is the faith manifest.
حَدَّثَنِي زُهَيْرُ بْنُ حَرْبٍ، حَدَّثَنَا جَرِيرٌ، عَنْ سُهَيْلٍ، عَنْ أَبِيهِ، عَنْ أَبِي هُرَيْرَةَ، قَالَ جَاءَ نَاسٌ مِنْ أَصْحَابِ النَّبِيِّ صلى الله عليه وسلم فَسَأَلُوهُ إِنَّا نَجِدُ فِي أَنْفُسِنَا مَا يَتَعَاظَمُ أَحَدُنَا أَنْ يَتَكَلَّمَ بِهِ ‏.‏ قَالَ ‏"‏ وَقَدْ وَجَدْتُمُوهُ ‏"‏ ‏.‏ قَالُوا نَعَمْ ‏.‏ قَالَ ‏"‏ ذَاكَ صَرِيحُ الإِيمَانِ ‏"‏ ‏.‏
Reference: Sahih Muslim 132 a
In-book reference: Book 1, Hadith 247
USC-MSA web (English) reference: Book 1, Hadith 239

Imam Al-Nawawi said in his commentary on this hadeeth:

“The Prophet’s words, ‘That is a clear sign of faith’ means, the fact they think of this waswaas as something terrible is a clear sign of faith, for if you dare not utter it and you are so afraid of it and of speaking of it, let alone believing it, this is the sign of one who has achieved perfect faith and who is free of doubt.”

Shaytaan only whispers to those whom he despairs of tempting, because he is unable to tempt them. As for the non-Muslims, he can approach them in any manner he wants and is not restricted to waswaas, rather he can play with them however he wants. Based on this, what the hadeeth means is that the cause of waswaas is pure faith, or that waswaas is a sign of pure faith.
The fact that one hates waswasas and that one's heart recoils from it is a clear sign of faith. Waswaas happens to everyone who turns to Allah by reciting dhikr etc. It is inevitable, but you have to be steadfast and patient, and persevere with your dhikr and prayer, and not give up, because in this way you will ward off the plot of the Shaytaan.
Indeed, the plot of Satan has ever been weak[Quran 4:76]

Every time a person wants to turn to Allah, waswaas brings other matters to mind. The Shaytaan is like a bandit: every time a person wants to move towards Allaah, he wants to block the way.

Remedy from Sunnah:
What's the remedy? Do we have any advice in Sunnah on this issue?
1. Say Aozubillahi and spit drily toward you left shoulder:

Uthman b. Abu al-'As reported that he came to Allah's Messenger (ﷺ) and said:

Allah's Messenger, the Satan intervenes between me and my prayer and my reciting of the Qur'an and he confounds me. Thereupon Allah's Messenger (ﷺ) said:, That is (the doing of a) Satan (devil) who is known as Khinzab, and when you perceive its effect, seek refuge with Allah from it and spit three times to your left. I did that and Allah dispelled that from me.
حَدَّثَنَا يَحْيَى بْنُ خَلَفٍ الْبَاهِلِيُّ، حَدَّثَنَا عَبْدُ الأَعْلَى، عَنْ سَعِيدٍ الْجُرَيْرِيِّ، عَنْ أَبِي، الْعَلاَءِ أَنَّ عُثْمَانَ بْنَ أَبِي الْعَاصِ، أَتَى النَّبِيَّ صلى الله عليه وسلم فَقَالَ يَا رَسُولَ اللَّهِ إِنَّ الشَّيْطَانَ قَدْ حَالَ بَيْنِي وَبَيْنَ صَلاَتِي وَقِرَاءَتِي يَلْبِسُهَا عَلَىَّ ‏.‏ فَقَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم ‏ "‏ ذَاكَ شَيْطَانٌ يُقَالُ لَهُ خِنْزِبٌ فَإِذَا أَحْسَسْتَهُ فَتَعَوَّذْ بِاللَّهِ مِنْهُ وَاتْفِلْ عَلَى يَسَارِكَ ثَلاَثًا ‏"‏ ‏.‏ قَالَ فَفَعَلْتُ ذَلِكَ فَأَذْهَبَهُ اللَّهُ عَنِّي ‏.‏
Reference: Sahih Muslim 2203 a
In-book reference: Book 39, Hadith 92
USC-MSA web (English) reference: Book 26, Hadith 5463

2. Pray loudly (loud enough that you can hear your own voice) when no one is close by for any prayer during night time:

It was narrated from Abu Qataadah (May Allah be pleased with him) that the Prophet (peace and blessings of Allah be upon him) went out at night, and he saw Abu Bakr (may Allah be pleased with him) praying in a low voice, then he passed by ‘Umar ibn al-Khattaab (may Allah be pleased with him) who was praying in a loud voice. When they met with the Messenger of Allah (peace and blessings of Allah be upon him), the Prophet (peace and blessings of Allah be upon him) said: “I passed by you, O Abu Bakr, and you were praying in a low voice.” He said: I made the One with Whom I was conversing hear me, O Messenger of Allah. And he said to ‘Umar: “I passed by you and you were praying in a loud voice.” He said: O Messenger of Allah, I wake up the sleeper and drive away the shaytaan. The Prophet (peace and blessings of Allah be upon him) said: “O Abu Bakr, raise your voice a little.” And he said to ‘Umar: “Lower your voice a little.” [Narrated by Abu Dawood and classed as saheeh by al-Nawawi in al-Majmoo’]

The scholars (may Allah have mercy on them) said that what is prescribed is for the worshipper to recite quietly in naafil/Sunnah prayers during the day, and he has the choice between reciting out loud or quietly during the night, because both are proven from the Messenger (peace and blessings of Allah be upon him), but reciting out loud is better. I have personally used this method extensively and have found it very beneficial to repel any thoughts which come during prayer.
Other tips for focus in prayers:
The following are few things that help one to develop the proper focus:

1. Know who Allah is. Learning meanings of His names and attributes.
2. Seek more knowledge.
3. Striving to think about what you are saying and doing, pondering the meanings of the Qur'an, dhikr and du’aa’s that you are reciting; bearing in mind that you are conversing with Allah as if you can see Him. For when the worshipper stands to pray, he is speaking to his Lord, and ihsaan means worshipping Allah as if you are seeing Him, and knowing that even though you cannot see Him, He sees you.
4. Striving to ward off the things that may distract you during prayer, namely thinking about things that are irrelevant or distracting. This is why praying Sunnah before Fard is helpful to guard our Fard prayers. Sunnah before fard are like warming up before you start the actual workout. Sunnahs after fard are like stretching after workout which helps to provide peace to your soul.
5. keep on turning to Allah in all situations, and to ask Him for help, and to beseech Him, and to ask Him to make us steadfast until death, and to cause us to die doing righteous deeds.