What is the ruling on one who takes money to perform Hajj on behalf of another, when his intention is solely to accumulate wealth?

If a person performs Hajj for worldly gain and takes money, this is impermissible (haram), and it is not lawful for him to mix the intention of an act of the hereafter with worldly desires, based on the Almighty's saying: ﴿Whoever desires the life of this world and its adornments - We fully repay them for their deeds therein, and they therein will not be deprived. Those are the ones for whom there is nothing in the Hereafter but the Fire. And wasted is what they did therein, and worthless is what they used to do.﴾ However, if he takes money to assist him in performing Hajj on behalf of another, then there is no harm in this. His intention would be to fulfill the need of the money's owner and to draw closer to Allah the Almighty.