Is writing the letter "Sa" in place of "sallallahu alayhi wa sallam" sufficient?

Question:
And another says: Sometimes, when we are writing and we come across the name of the Messenger (peace and blessings be upon him), we write the letter "Sa" in place of "sallallahu alayhi wa sallam." Is this sufficient?

Answer:
No, it is not appropriate. If the writer writes the name of the Prophet (peace and blessings be upon him), he should write "sallallahu alayhi wa sallam" in full. He should not write "sallallahu" or "salla," no, he writes it in full so that he obtains the great reward. Whoever sends blessings upon him, Allah sends blessings upon him. Do not be lax, do not be cowardly or lazy. Yes, it is not sufficient. The scholars have pointed this out. Some people do not pay attention to it; they leave it as "salla" without knowing that it is "sallallahu alayhi wa sallam." We pass over it, and he says "Salih,"