Whoever strives for the purpose of worldly gains...

Surah Ash-Shura

"and whosoever desires the reward of this world, We give him thereof, and he has no portion in the Hereafter." [42:20]
- means, whoever strives for the purpose of worldly gains, and never pays any heed to the Hereafter at all, Allah will deny him the Hereafter; and in this world, if He wills He will give to him and if He does not will, he will gain neither. 
- So the one who strives with this intention in mind will have the worst deal in this world and in the Hereafter. The evidence for that is the fact that this Ayah is reinforced by the passage in Subhan (i.e., Surat Al-Isra') in which Allah says:
"Whoever desires the quick-passing, We readily grant him what We will for whom We like. Then, afterwards, We have appointed for him Hell; he will (enter) burn therein disgraced and rejected. And whoever desires the Hereafter and strives for it, with the necessary effort due for it while he is a believer -- then such are the ones whose striving shall be appreciated. On each -- these as well as those -- We bestow from the bounties of your Lord. And the bounties of your Lord can never be forbidden. See how We prefer one above another (in this world), and verily, the Hereafter will be greater in degrees and greater in preferment." [17:18-21]

Allahu Akbar! May Allah forbid us to ever be heedless with regards to the hereafter, and may He give us joy and bliss in every stage of the hereafter, ameen