Adab al-Mufrad

Benefits and Issues:
➊ Every person's supplication (dua) is certainly accepted sooner or later, as long as the person does not become hasty. Haste is when one says: "I make supplication but it is not accepted." To the extent that Allah even grants the supplication of a disbeliever, whether He gives it in this world itself. As for the believer, he either receives what he asked for, or Allah grants him something better, or due to the supplication, some calamity is averted from him, or Allah stores his supplication for the Hereafter.

➋ The individuals mentioned in the hadith receive exactly what they seek, provided that no obstacle comes in the way. For example: if the oppressor seeks forgiveness from the oppressed, or a child apologizes to the parents by being obedient, etc., or if the traveler’s food, drink, and clothing are unlawful.

➌ The more insistence (ilhaah) and humility and weeping there is in supplication, the greater the chances of its acceptance. A supplication made with a heedless heart and indifference cannot attain the status of acceptance with Allah. Since the oppressed is in extreme difficulty and distress, due to helplessness a cry comes from his heart which reaches directly to the Divine Throne. In some narrations, it is mentioned that even if the oppressed is a disbeliever, his supplication is accepted. The Messenger of Allah (sallallahu alayhi wa sallam) said: "Allah opens the gates of the heavens for his supplication and says:
﴿وَعِزَّتی لَأَنْصُرنَّكَ وَلَوْ بَعْدَ حِیْنٍ﴾
'By My Honor! I will surely help you, even if it is after some time.'" (Sunan al-Tirmidhi, Hadith: 3598)
Among the mutual rights of Muslims is also included that the oppressed should be helped. (Sahih al-Bukhari, Hadith: 2445, and Sahih Muslim, Hadith: 2066)

➍ Among all the causes for the acceptance of supplication, one cause is travel, provided that the journey is not for disobedience to Allah. Many incidents are narrated from the Messenger of Allah (sallallahu alayhi wa sallam) regarding supplication during travel. Although all times of a Muslim are extremely precious, the times of travel should be considered an opportunity, and one should make abundant supplications for oneself and for friends and loved ones. It is regrettable that in the present era, Allah has made travel so easy, yet people neither remember Allah during travel nor make supplication; rather, they waste the precious moments of their journey listening to songs and watching films, and many unfortunate ones even meet death in this very state. May Allah protect us. The wisdom behind the acceptance of supplication during travel is best known to Allah, however, it is understandable that a person, being away from his family during travel and feeling estrangement due to unfamiliarity, turns to Allah with sincerity. And a supplication made with sincerity attains the status of acceptance with Allah.

Another cause for the acceptance of supplication is that a person should not be in luxury and comfort, but rather should ask Allah as a beggar, as the Messenger of Allah (sallallahu alayhi wa sallam) used to go out to seek rain. In other narrations where the supplication of the traveler is mentioned, the state of that traveler is described as:
((Ash'ath aghbar yamuddu yadayhi... al-hadith))
"Disheveled hair, clothes covered in dust, and he raises his hands in supplication...."
Similarly, the command not to apply perfume or comb the hair while in the state of ihram also indicates that the reason for the acceptance of the traveler's supplication is his estrangement and disheveled state.

➎ Parents and teachers always desire the progress of their children and students and never feel envy. Similarly, it is rare for a curse (bad-dua) to come from their mouths. If parents curse someone, it clearly means that the person has caused them so much pain that, despite parental affection, they have been compelled to supplicate against him, and their curse is not merely words but heartfelt anguish that immediately reaches the Divine Throne. Therefore, a person should always avoid the curses of parents and strive to please them and obtain their supplications.