Reference: Sharh ‘Umdatil-Fiqh – Tape No.9, Question No.46
Question: [The Prophet (sal-Allaahu ‘alayhi wa sallam) said:]
«When the iqaamah for the prayer is called, there is no [other] prayer other than the prescribed [obligatory prayer]» [from the hadeeth of Abu Hurayrah, as transmitted by Muslim 1/493].
…and you mentioned that the [voluntary] prayer must be terminated; so how do you terminate it, would it be by the tasleem?
Response: The [voluntary] prayer can be terminated by the tasleem or without the tasleem; what is important is that it be terminated.