Praise be to Allah, and peace and blessings be upon the Messenger of Allah. To proceed:
Supplication is one of the greatest means that Allah Almighty has legislated for attaining what one seeks and warding off hardships. It is itself included within the decree of Allah Almighty. As for the hadith “You would only marry the woman who was decreed for you,” it is a weak hadith and cannot be used as evidence. It does not contradict the authentic texts concerning the virtue and legitimacy of supplication.
It is established in the Sunnah that supplication is one of the means of warding off affliction and attaining goodness. Among the evidence is the hadith of Salman, may Allah be pleased with him, in which the Prophet ﷺ said:
“Nothing repels the decree except supplication, and nothing increases one's lifespan except righteousness.”
Narrated by al-Tirmidhi (2139), who said: “This is a hasan gharib hadith.”
The fact that supplication is a means of warding off affliction or changing what befalls a person does not mean that supplication falls outside the decree of Allah Almighty. Rather, supplication itself is part of the divine decree.
Shaykh al-Islam Ibn Taymiyyah, may Allah have mercy on him, said:
“He is the One who created the cause and the effect, and supplication is among the causes that Allah, Glorified and Exalted is He, has decreed.”
Allah Almighty has decreed matters and has decreed their means as well. Just as He has decreed healing, He has decreed means for it, such as medicine. Likewise, just as He has decreed that certain things will occur, He has decreed means for them, including supplication, striving, and other causes.
The hadith which states:
“Even if Israfil, Jibril, Mika'il, the Bearers of the Throne, and I among them were to supplicate for you, you would not marry anyone except the woman who was decreed for you.”
was narrated by Ibn 'Asakir in Tarikh Dimashq, through a chain containing Maslamah ibn 'Ali, who is very weak.
Al-Hafiz Ibn Hajar, may Allah have mercy on him, said concerning Maslamah ibn 'Ali al-Khushani:
“Abandoned.”
The chain also contains Muhammad ibn Kharashah, who is unknown. Al-Dhahabi, may Allah have mercy on him, said:
“A shaykh who is unknown.”
Ibn Abi Hatim also transmitted from his father that the hadith is mursal rather than musnad.
For this reason, Shaykh al-Albani classified the hadith as weak in Da'if al-Jami' al-Saghir (4823).
Thus, the hadith is not authentically attributed to the Prophet ﷺ, and it cannot be used to oppose the established hadiths that encourage supplication and explain its virtue and effect.
The fact that marriage is decreed does not mean that one should abandon supplication, because supplication is among the means that Allah has decreed for reaching what has been decreed.
A person does not know what Allah has written for him. Therefore, he is instructed to ask Allah for goodness, to supplicate Him to grant what he hopes for, and to seek His help in all his affairs.
If a person knew that supplication had no effect, the prayer of Istikhara would not have been legislated for him when undertaking important matters, including marriage.
It is authentically reported from Jabir, may Allah be pleased with him, that he said:
“The Prophet ﷺ used to teach us Istikhara in all matters just as he used to teach us a surah from the Qur'an...”
Then the Prophet ﷺ mentioned the supplication of Istikhara, including:
“O Allah, if You know that this matter is good for me in my religion, my livelihood, and the outcome of my affair—or he said: in the immediate and future aspects of my affair—then decree it for me. And if You know that this matter is bad for me in my religion, my livelihood, and the outcome of my affair—or he said: in the immediate and future aspects of my affair—then turn it away from me and turn me away from it, and decree goodness for me wherever it may be, then make me content with it.”
Narrated by al-Bukhari (6382).
This supplication clearly demonstrates that the servant asks Allah to decree goodness for him and to turn away from him what contains harm. Therefore, it is incorrect to say that knowing everything is decreed makes supplication useless.
The hadith: “Even if Israfil, Jibril, Mika'il, the Bearers of the Throne, and I among them were to supplicate for you, you would not marry anyone except the woman who was decreed for you” is weak. It is therefore not correct to attribute it to the Prophet ﷺ or to use it as evidence in this matter.
As for supplication, it is a great legislated means and is included within the decree of Allah Almighty. Allah has decreed the outcomes as well as their means, among which are supplication, Istikhara, and taking the appropriate means.
Therefore, if a person wishes to marry or pursue any other worldly matter, he may ask Allah for whatever he wishes, perform Istikhara, ask Him to decree goodness for him wherever it may be, and then make him content with it.
And Allah knows best.