What is the Shari’ah ruling with regards making Jama’a of two Salaah, eg Maghrib and Esha together?
I need a more detailed explanation because I was shown a Hadeeth which say’s Prophet Sallallahu Alayhi Wasallam combined Salaahs when travelling.
In the name of Allāh, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-raḥmatullāhi wa-barakātuh.
Salaah is one of the pillars of Islam. In the Shari’ah the way of performing Salaah is prescribed as are the times for performing each Salaah. Just as Allah Ta‘ala says in the Holy Qur’an, “Verily Salaah has been decreed upon the believers a decree of specified times.”
Allah Ta‘ala has made this a command by stating the above Ayat in the Holy Qur’an.
The truth about when to perform each Salaah was given via Jibreel (Alayhissalam) to Rasulullah (Sallallahu Alayhi Wasallam). Sayyidina Abdullah ibn Abbas (RadiAllahu anhu) narrates that the Rasulullah Sallallahu Alayhi Wasallam said: ‘That Jibreel Alayhissalam came for two days to the Kabaa and lead the Salaah. On the first day, he performed each Salaah at the beginning of the time for each Salaah and on the second day he made me perform each Salaah at the end of the time for each Salaah. Then he said to me O Muhammad (Sallallahu Alayhi Wasallam) these are the times of the Salaah of the Prophets (Alayhimussalam) before you. So hence you and your Ummah should perform each Salaah in between the beginning and end time for each Salaah’.
Sayyidina Abdullah ibn Mas’ood (RadiAllahu anhu) says that the prophet Sallallahu Alayhi Wasallam used to perform each Salaah at is prescribed time except on the day of Muzdalifah and Arafaat. 
Imaam Muhammad Shaibani (Rahmatullahi) narrates that a Hadeeth has reached us from Sayyidina Umar (RadiAllahu anhu) that he sent letters to all the governors of all the Muslim lands informing them that they should not combine two Salaah. Performing two Salaah at one time is a major sin.
The verse of the Holy Qur’an, the Sunnah of Rasulullah Sallallahu Alayhi Wasallam (except during Hajj at Arafaat and Muzdalifah) and the actions and advice of the Sahabah (RadiAllahu anhum) proves that the combining of two Salaahs at one time is not permissible.
Those Hadeeth that apparently show the combining of two Salaahs by Rasulullah Sallallahu Alayhi Wasallam are in reality not the combining of two Salaahs. Each Salaah was performed during the prescribed time for that Salaah not at one time. There are two types of making this Jama’a,
a) Jama’a Haqeeqe (In reality performing two Fard Salaah together during the time of a Fard Salaah. For example, if both Maghrib and Esha are performed straight after sunset, or After Zawaal, performing both Zuhr and Asr Salaah together). This is not permissible in any situation. In the Hanafi Fiqh this is not permissible even during a journey. Jama’a Suree (Where it looks like two Salaah are performed together but in reality both the Salaah are being performed during their prescribed times. For example, for a special reason Magrib Salaah is delayed until the final time for Maghrib and afterwards Esha is performed right at the beginning of Esha time, or Zuhr Salaah is performed at the end of Zuhr time and Asr is performed at the beginning time for Asr. This in reality is performing each Salaah during the prescribed time. This is permissible during a time of hardship such as during illness or when on a journey. The Ahadeeth that appear to show the Prophet Sallallahu Alayhi Wasallam performing Salaah together is in fact Jama’a Suree. If these Ahadeeth are interpreted as being Jama’a Haqeeqe then this interpretation is against the command of Allah from the Holy Qur’an, against Saheeh Ahadeeth and the advice of the Sahabah (RadiAllahu anhum) and would be against the rulings of Shari’ah. It is therefore clear that Jama’a Haqeeqe is not permissible as there is no valid proof. There is only proof for Jama’a Suree. 
Mufti Muhammad Yusuf Danka,
Croydon Musjid Islamic Centre
Checked and Concurred by,
Mufti Luqman Hansrot
 (Idaahul Tahawi, vol 1, Page 467/ Majmu’a tul Fataawa vol 1, page 293/ Aujazul Masalik vol 3, Page 147)
أخّر الظهر وعجّل العصر، وأخّر المغرب وعجّل العشاء … قد صرح بأن ما رواه من الجمع المذكور هوالجمع الصوري
(أوجزالمسالك ,ج3, ص147( )نيل الأوطار ج2 ,ص491( )شرح معاني الآثار ج1, ص160( )بذل المجهول ج6 ,ص286)