al-Fawaa’id, pp 151-152, Al-Istiqaamah, No. 2
So what has preceded can be rectified by tawbah (repentance), nadam (regret) and istighfar (seeking Allaah’s forgiveness). And this is something that will neither tire you, nor cause you to toil as you would with strenuous labour. Rather it is an action of the heart.Then as regards the future (then it can be corrected) by withholding yourself from sins. And this abandonment is merely the leaving of something and to be at ease from it. This also is not action of the limbs, which requires you to strive and toil. Rather this is a firm resolve and intention of the heart – which will give rest to your body, heart and thoughts.
So as for what has preceded, then you rectify it with repentance. And as for the future – then you rectify it with firm resolve and intention. Neither of these involves any hardship or exertion of the limbs.
But then your attention must be directed to your life in the present – the time between two times. If you waste it, then you have wasted the opportunity to be of the fortunate and saved ones. If you look after it, having rectified the two times – what is before and after it, as we have said – then you will be successful and achieve rest, delight and ever-lasting bliss. However, looking after it is harder than that which comes before and after it, since guarding it involves keeping to that which is most befitting and beneficial for your soul, and that which will bring it success and well-being.