Reference: Silsilah Kitaab ad-Da ‘wah (1), al-Fataawa – Volume 1, Page 74
Question: Is there any evidence to suggest that the Messenger of Allaah ﷺ raised his hands in supplication after the obligatory prayer itself, since there are those who have said to me that he would not raise his hands in supplication after the obligatory prayer?
Response: It is not authenticated that the Prophet ﷺ would raise his hands after the obligatory prayer, and nor has it been authenticated that the companions (radhi-yAllaahu ‘anhum) [would do so] from that which we know. So that which some people do in raising their hands after the obligatory prayer is an innovation which has no basis, for that which the Prophet ﷺ said:
«Whoever does an act which is not in agreement with us (i.e. Allaah (subhaanahu wa ta’aala) and Muhammad ﷺ) then it will be rejected», [Muslim transmitted it in his Saheeh].
And [likewise] he ﷺ said:
«Whoever introduces anything into this matter of ours (i.e. Islaam) that which is not from it, will have it rejected», [It’s authenticity is agreed upon by both Imaam al-Bukhaaree and Imaam Muslim]