I heard that it is Bid'ah or not right to read Du'a after praying and that it should be before it. They say there is no Hadith that says the Prophet (Sallallahu Alaihi wa Sallam) did so. Is it true?
All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
Supplicating after the prayers is proved and even desirable in general. This is the opinion of the majority of Muslim scholars. It is not an innovation as supposed by some people.
Imam Al-Bukhari entitled a chapter in his book by this: “Invocation after the Prayer.” Under this title, he mentioned the Hadeeth that the Prophet used to say at the end of every prayer after the Tasleem:
('None has the right to be worshipped except Allah, Alone, without partner, to Him belongs all Sovereignty and Praise and He is over all things Omnipotent. O Allah, none can prevent what You have willed to bestow and none can bestow what You have willed to prevent, and no wealth or majesty can benefit anyone, as from You is all wealth and majesty').
Imam Ibn Hajar wrote explaining the above Hadeeth that what is claimed by some people that making Du'aa’ after the Prayers is not permissible at all is incorrect. He also mentioned many Ahadeeth that prove that the Prophet ordered some of the companions to supplicate after the Prayers. For example, he taught Muath to invoke Allah after Prayers with these words: ('O Allah, help me remember You, to thank You, and to worship You in the best of manners').
Another Hadeeth reported from Imam Muslim reads that the Prophet used to say after ending his prayer."
('O Allah, set right for me my religion which is the safeguard of my affairs. And set right for me the affairs of my world wherein is my living. And set right for me my Hereafter on which depends my afterlife. And make the life for me (a source) of abundance for every good and make my death a source of comfort for me protecting me against every evil').
Those who do not allow invocations just after the Prayers are of the view that doing so is not permissible before uttering the established invocations that are proved from the Prophet Muhammad . However, they permit making Du'aa’ for the one who starts first with the supplications that are normally invoked after Prayers.
It is apparent from the given details that making Du'aa’ after the Prayers is permissible. Thus, no one should be condemned; i.e., neither the one who supplicates nor the one who leaves it. This matter is flexible and falls under the general ruling of making Du'aa’.
For more benefit, one may refer to Fath-al-Bari, vol: 11, Page, 137-138.
Know that if this Du'aa’ is made in a specific form, such as when the Imam makes Du'aa’ and others say 'Ameen', and it is practiced continuously, then it becomes an innovation.
Allah knows best.