Is Praying Fast Prohibited?
Question

I pray quickly, i.e., I recite Surat Al-Fatihah and other short Surahs quickly, and my movements during the prayer are also fast. Is this permissible or not?
Praise be to Allah.Shaykh `Abd Al-`Aziz ibn Baz (may Allah have mercy on him)  said:
Significance of Measured Recitation in Islam
The Sunnah is for the one who is reciting to recite at a measured pace (Tartil) and not to rush, so that he may ponder and think about what he is reciting, whether it is Al-Fatihah or something else. The Sunnah is to ponder, think and recite at a measured pace, not to rush. Allah, may He be Exalted, says (interpretation of the meaning): 
{And recite the Quran (aloud) in a slow, (pleasant tone and) style.} [Al-Muzzammil 73:4] 
{(This is) a Book (the Quran) which We have sent down to you, full of blessings, that they may ponder over its Verses, and that men of understanding may remember.} [Sad 38:29] 
Reading so fast that some letters or verses are not pronounced properly is not permissible; rather the worshipper should recite slowly and not be hasty, so that the recitation will be correct and clear, and he can ponder and think about (what he is reciting). 
If he omits or changes some of the letters, this is a kind of recitation that is not permissible. Rather he has to recite carefully and at a measured pace, so that the letters and words are pronounced in full. 
Is praying fast prohibited?
The same applies to prayer, he should not rush when bowing or prostrating, or when sitting between the two prostrations, or when standing after bowing. Rather he should move with deliberation and calmly . This is what is required. Moving calmly is an essential obligation; “pecking” and moving hastily in prayer invalidates the prayer. 
Recommended supplications during prayer
We advise the questioner to move carefully and calmly when bowing, and not to rush; he should say Subhana Rabbiya Al-`AdhIim three or more times, and he should say: Subhanaka Allahumma wa bi hamdika, Allahumma ighfir li (Glory be to You, O Allah, and praise; O Allah, forgive me). When he raises his head from bowing he should settle into the standing posture and say: Rabbana wa lakal-hamd, hamdan kathiran tayyiban mubarakan fihi mil’a As-Samawati wa mil’a Al-Ard wa mil’a ma baynahuma wa mil’a ma shi’ta min shay’in ba`d (Our Lord, to You be praise, much good and blessed praise, filling the heavens, filling the earth, filling what is between them and filling whatever You will besides). This is what is best for him. 
Saying Rabbana wa lakal-hamd is obligatory according to the correct opinion. If he completes it by saying hamdan kathiran tayyiban mubarakan fihi mil’a As-Samawati wa mil’a Al-Ard wa mil’a ma baynahuma wa mil’a ma shi’ta min shay’in ba`d, that is more complete and better. 
And some extra words were narrated from the Messenger (blessings and peace of Allah be upon him): “Ahl Ath-thana’ wal-majd, ahaqqu ma qala Al-`abd, wa kulluna laka `abd, la mani` lima a`tayta wa la mu`ti lima mana`ta, wa la yanfa`u dhal-jaddi minka Al-jadd (You are the One Who most deserves praise and glorification, (this is) the soundest thing a slave could say, and we are all Your slaves; none can withhold what You give, and none can give what You withhold, and the good fortune of any fortunate person is to no avail against You). This is perfection of praise. 
Similarly when prostrating, he should not rush, and he should prostrate on the seven parts: the forehead, the nose, the hands, the knees and the toes; he should settle in the posture and not rush, and he should say Subhan Rabbi Al-A`la, Subhan Rabbi Al-A`la, Subhan Rabbi Al-A`la, subhanaka Allahumma wa bi hamdika Allahumma ighfir li (Glory be to my Lord Most High. Glory be to my Lord Most High, Glory be to my Lord Most High, Glory be to You, O Allah, and praise, O Allah, forgive me). 
He should offer whatever supplication he can, and say: Allahumma ighfir li dhanbi kullahu diqqahu wa jullahu, awwalahu wa akhirahu, `alaniyatahu wa sirrahu (O Allah, forgive me all my sins, small and great, first and last, open and secret). This is a prescribed Du`a. 
And the Prophet (blessings and peace of Allah be upon him) said: “The closest a person is to his Lord is when he is prostrating, so offer a lot of Du`a then.” And he said: “As for prostration, strive hard in supplication, because it is more likely that you may receive a response.” 
The proper way to prostrate and sit in prayer
The believer should not rush when prostrating; rather he has to settle in the position, as this is one of the essential parts of prayer and is necessary. Yet it is prescribed not to pause too long (in any position) and not to rush, and he should offer Du`a whilst prostrating and repeat the words Subhana Rabbiya Al-A`la. What is obligatory is to say it once, but repeating it three or five or seven times is better. 
Between the two prostrations he should also settle in the posture and not rush. He should sit up between the two prostrations until every vertebra returns to its place, and he should say, Rabb ighfir li, Rabb ighfir li, Rabb ighfir li, Allahumma ighfir li warhamni wahdini wajburni warzuqni wa `afini (Lord forgive me, Lord forgive me, Lord forgive me, O Allah forgive me, have mercy on me, guide me, comfort me, grant me provision, and grant me well being). 
All of that was narrated from the Prophet (blessings and peace of Allah be upon him) and the Muslim should follow the example of his Prophet (blessings and peace of Allah be upon him) and do as he did, and he should not be hasty in such matters, for prayer is the foundation of Islam and prayer is an important matter. 
Striving for excellence in prayer
So we advise the questioner to pay attention to this matter and to fear Allah and remember that He is always watching; he should do his prayer at a measured pace, and not rush. Similarly, his recitation should be slow and careful, and not rushed; rather he should recite clearly, pondering and thinking about (what he is reciting), and try to benefit from it. We ask Allah to help and guide us all. (End quote)
For more details, please see the following answers: 6 , 132081 , 12683 , 228520 , 131850 .