Hajj has a special merit that other acts of obedience do not have, in that it clears one of all sins, enormous and small. The Prophet, sallallahu ^alayhi wa sallam, said:

مَنْ حَجَّ فَلَمْ يَرْفُثْ وَلَمْ يَفْسُقْ خَرَجَ مِنْ ذُنُوبِهِ كَيَوْمَ وَلَدَتْهُ أُمُّهُ

Man hajja falam yarfuth wa lam yafsuq kharaja min dhunubihi kayawma waladat-hu ummuh.

Which means: “Whoever performs Hajj without copulating or committing enormous sins is clear of his sins as he was on the day his mother gave birth to him.”