Concerning the story of Musa, Allah ﷻ says,
“When he arrived at Midian’s waters, he found a group of men watering [their flocks], and beside them two women keeping their flocks back, so he said, ‘What is the matter with you two?’ They said, ‘We cannot water [our flocks] until the shepherds take their sheep away: our father is a very old man.’ He watered their flocks for them, withdrew into the shade, and prayed, ‘My Lord, I am in dire need of whatever good thing You may send me,’” [Qasas (28):23-24]
As a consequence of this small sincere action, Musa was given:
1) Safety: “‘Do not be afraid, you are safe now from people who do wrong.’” [Qasas (28):25]
2) Employment: “One of the women said, ‘Father, hire him: a strong, trustworthy man is the best to hire.’” [Qasas (28):26]
3) A spouse: “The father said, ‘I would like to marry you to one of these daughters of mine,’” [Qasas (28):27]
4) Messengership: “But when he reached it, a voice called out to him from the right-hand side of the valley, from a tree on the blessed ground: ‘Musa, I am Allah, the Lord of the Worlds.’” [Qasas (28):30]
~ Ustadh Alamgir Islam
Shaikh Ibn ‘Uthaimeen:
The first condition.
Sincerity to Allah.
The person is sincere in his du’a.
Knowing that Allah is All-capable to answer his du’a.
Expecting the response from Allah.
The person’s aware of his situation when supplicating.
That he’s in the most dire need, rather in the most dire necessity for Allah.
(Believing) that Allah’s the One who answers the call of the one in distress if he calls to Him and removes the evil.
As for supplicating to Allah and he feels he is independent of Allah, and that he’s not in necessity and he asks Him like this, a custom only, then this is not likely to be answered.
That he avoids consuming haraam.
For surely, haraam is a barrier between a person and the answer of du’a.
Source: Fatawa Noor ‘alaa al-Darb (no. 324)
Imam Ibn ul-Qayyim رحمه الله
“If Allah wants well for a slave, He strips away from his heart the ability to see his own good deeds and speaking about them with his tongue, and preoccupies him with seeing his own sin, and it continues to remain in front of his eyes until he enters jannah.”
[Tareeq Al- Hijratain,1/168-169]
‘If a slave finishes the Qur’an (khatm), an Angel kisses him in-between his eyes.’ — • ‘Isa bin Yunus (rahimahullah)
Hilyat al-Awliya, by Abu Nu’aym (8/355)
Before you make du’aa it’s worth knowing:
“Invoking Allah’s name al-Qayyum has a special effect in answering du’aas and ending afflictions.” —•
Ibn al-Qayyim, Prophetic Medicine (p. 257)
“Allāh has hidden Laylat-ul-Qadr from His slaves as a mercy for them so that they may seek it while increasing in good deeds by their prayer, Dhikr, Du’ā and getting closer to the Lord and Allāh has hidden this night so that it may become clear who strives diligently in seeking it as opposed to the one who has taken it lightly out of laziness.”Sh. Ibn al-‘Uthaymeen Raḥimahullāh [مجالس شهر رمضان]