Question: Why did Shaikh Ahmed Tidjani, may ALLAH be pleased with him, advised us to recite Surat el Fatiha in this way: the "Basmala" linked with Surat el Fatiha?
The following Hadith Qudsi is one of the reasons why our beloved Master Ahmed Tidjani (may ALLAH sanctify his precious secret) advised us to read it this way:
Abu Bakr As Sadiq (may ALLAH be satisfied with him) related:
“By ALLAH The Most High, Muhammad al Mustafa related to me:
By ALLAH The Most High, Jibril (peace be upon him) related to me:
By ALLAH The Most High, Israfil (peace be upon him) related to me:
ALLAH, may HE be exalted, said: “ O Israfil, by MY ALMIGHTY POWER, MY MAJESTY, MY GENEROSITY and MY NOBLENESS, he who recites: “In the Name of ALLAH, the Entirely Merciful, the Especially Merciful” immediately followed by the Fatiha of The Book one single time, bear witness that I have forgiven him, that I have accepted his good deeds and rejected his bad deeds. I will not burn his tongue in the fire, I will protect him from the chastisement of Hell, from the chastisement of Resurrection and from the great fear. He will meet with Me before the Prophets and the Saints!””
So we read it as it is pronounced in the following audio files: audio1 - audio2 ("BISMILLAHIRAHMANIRAHIMILHAMDULILLAHIRABBILALAMIN"), during obligatory and non-obligatory prayers (Salat), and when accomplishing lazim, wazifa, hadra, etc...
Note: For example, if a person leads the congregational prayer and knows that linking the "Basmala" with the Fatiha could be a cause of argument, then of course avoiding any polemic is preferable and so in such circumstances we do not link them with one another.