Praise be to Allah, and may peace and blessings be upon the Messenger of Allah.
There is no contradiction between believing in divine decree and making supplication, performing Istikhara, and taking the necessary means; for Allah تعالى has decreed things and has also decreed their means. Therefore, outcomes do not occur without the means that Allah has made a pathway to them.
Supplication is among the greatest means that Allah تعالى has legislated. He says: ﴿And your Lord has said: “Call upon Me; I will respond to you.”﴾ [Ghafir: 60]. Likewise, Istikhara is a means of seeking goodness from Allah تعالى and asking Him to make easy for His servant what contains goodness and to turn away from him what contains evil.
When a servant makes supplication or performs Istikhara, his supplication and Istikhara are themselves part of Allah’s decree. Allah may have decreed that a particular matter will occur because of that supplication. Therefore, it is not correct for a person to say: “Since everything is already written, I will not make supplication and I will not take the necessary means.” Abandoning the means on the pretext of divine decree is a form of helplessness. The Prophet صلى الله عليه وسلم said: “Be keen on what benefits you, seek the help of Allah, and do not be helpless.”
Supplication may be a means of warding off a calamity, reducing its severity, or bringing about goodness, and all of this is within the decree of Allah تعالى. Divine decree does not cancel the means; rather, it includes both the means and the outcomes together.
Accordingly, Salat al-Istikhara is not an objection to divine decree. Rather, it is one of the greatest forms of turning to Allah. It involves entrusting the matter to Him, asking Him for what is good, while also taking the lawful and appropriate means.
Therefore, the Muslim must combine belief in divine decree, supplication and Istikhara, taking the necessary means, and reliance upon Allah, and he should not use divine decree as an excuse to abandon the means that Allah has prescribed.
And Allah تعالى knows best.