Does Allah forgive sins and grant steadfastness in obedience to one who was obedient then weakened, and will his Hajj be accepted?

One must persevere in striving against the self and compelling it towards what brings one closer to Allah. If the servant truly seeks refuge in Allah, He will aid him. If one does not recall certain sins, let him make a general repentance for all sins, and let him have a good opinion of his Lord, and strive diligently to please Him, and associate with the righteous. The burden of worship and the pain of striving will dissipate with patience in obedience, for the sweetness of faith is not attained except after striving.