Originally Posted by SintoDinto
I'd like to expand on this. Unworthy dua isn't a magic cure. Refer to a lecture on youtube: Tips on getting your duas answered.
Meaningful duas is the key for our (successful) efforts and ultimate goal. Could you imagine a person making all the efforts within his abilities and then not succeeding? (entirely possible) Versus, someone being assisted within his own efforts and doors/opportunities being opened for his eventual success and being guaranteed? Duas are important, especially when the believer recognizes his true status in front of His creator. That without Him, there is no believer to even begin with and that all power comes from Him. That is why perhaps it is stated that the best duas are made in the Sujood. What could be a more humble position of submission than that!
This is something to be considered carefully and not overlooked easily.
Worthy duas are the vehicle to achievements and our actions guide the answering . And at all points in time, Allah knows what is best for us, whether He answers, or does not respond to our duas or efforts. Also, He can delay our duas to be answered for a later time.
In anycase, death is always on time, so it's in the best interest to use all abilities and opportunities to become better in the given present moment
When making sincere duas (and efforts) know that outcomes are always in someone's best interest. Even when making a mistake it wouldn't be a person is doomed to the hellfire or the punishment in the grave, especially if Allah is guiding one to repent, do good deeds, fix the wrongs. Balance between hope and fear.
For the initial question involved the Quran advises us to do both
(1) supplicate to Allah for success in both words:
رَبَّنَا آتِنَا فِي الدُّنْيَا حَسَنَةً وَفِي الْآخِرَةِ حَسَنَةً وَقِنَا عَذَابَ النَّارِ
Al-Bakarah Verse 201
Rabbana atina fid-dunya hasanatan wa fil 'akhirati hasanatan waqina 'adhaban-nar
"Our Lord! Grant us good in this world and good in the hereafter, and save us from the chastisement of the fire"
(2) Strive hard (with utmost best efforts by doing what is right as mentioned) to work for success in both worlds:
"O ye who believe! save yourselves and your families from a Fire whose fuel is Men and Stones, over which are (appointed) angels stern (and) severe, who flinch not (from executing) the Commands they receive from Allah, but do (precisely) what they are commanded."
- Surah At-Tahrim (66:6)
The Power of dua (supplication)