Maulana Ashraf Ali Thanvi (rahmatullahi alaihi) says:
The best opinion, however, is to perform both of these things simultaneously. That is, to work on letting go of sins and displeasing acts whilst increasing your worship, zikr and connection with Allah. The realised (muhaqiq) Shaykhs are all in favour of this method, though the main thrust is always on what the seeker himself feels more attuned to.
Our Shaykhs always used to find out the temperament of the seeker before guiding him. Once, Maulana Muneer Nanotwi came to Haji sahab (Haji Imdadullah) and asked to be taken in for guidance. Haji sahab asked him 'Tell me, if there is a field with much weeds and dereliction, would you first clean it all up and root out the weeds and thistles, thereafter planting seed or would you first plant seed and clean it after?' Maulana answered 'I would plant the seed first - at least something will be there to reap, the cleaning could be later. We don't know how long the weeding might take and the season might be over by that time' Haji sahab laughed at that answer and decided the Naqshbandi method was best for him.
As I was saying, seeing the lack of free time, inclination, the short lifespans of the people at present, it was decided that the best method was to take both ways side by side - to clean and weed the terrain and plant the seeds as you clear it up.
There is not a more obvious example of this than in the prescribed practices of shar'iah. Where one is encouraged to sleep little (sleeping too much being displeasing) he is also told to worship Allah in that time in Tahajjud and Taraweeh. Similarly, one is not told to simply silence his tongue from lying and gossiping and idle talk, but also to recite the Quran and remember Allah at the same time.
In this method, there is a great benefit to be gained. The reason being that a lot of seekers of the pleasure of Allah fall prey to a mistake in this regard. That is that they exert themselves in trying to shun all relations and things around them, thinking that once I am free from these distractions I will be able to turn solely in attention to Allah. This is in itself a good intention, but sometimes he does not go about it the right way.
When he is cutting out from his life these 'wordly' things, he does not simultaneously fill his heart up with Allah's love and devotion. The result is that there comes a time when his heart is completely empty, since he did not actively engage his heart in connecting with Allah - or he aimed to but did not perform much effort in this regard, especially since connecting with Allah is actually connecting with an unseen thing which is difficult to immerse yourself in fully without due striving.
So, he has emptied his heart from all other things, but has not matched it with attaching himself to Allah's love, and his empty heart becomes easy prey for Shaytan.
So, to protect yourself from this danger, extricate yourselves from your wrong habits but at the same time fill in the vacuum with love for Allah, by increasing your good deeds and remembrance.
(Maulana Ashraf Ali Thanvi, Taqleel-ul-kalaam, pg 200-201, Published Maktaba Thanvi, Karachi. )