The statement you have quoted in your question is
correct, but the meanings sometimes construed from it are misleading. Indeed we
should devote time for the worldly affairs proportionate to its significance and
likewise for the Hereafter. However, that doesn’t imply that we should say
goodbye to the worldly obligations completely. Had that been Islam’s ideal, we
would have found the Prophet (sws) not participating in any worldly activity at
all. The fact that he fully participated in the worldly affairs is enough reason
for us to reject this understanding.
The truth of the matter is that we are expected to earn our
rewards for the Hereafter from this very life. That would require us to get
involved not only in worship but also in the ‘mundane worldly affairs’. However,
in the case of the latter activities, we are expected to abide by the rules laid
down by Islam. Thus if we carry out our worldly obligations in accordance with
the injunctions and the spirit of Islamic Sharī‘ah, we will be leading a fully
Hereafter-oriented life. The Prophet (sws) is reported to have said: ‘This world
is a cultivating ground for the Hereafter’.
As for the question of how an individual should allocate
his time for various possible engagements that would enable him to get the best
results (from the point of view of the Hereafter), there can be no one answer
for everyone. It depends on many factors: one’s circumstances, abilities, and
natural inclinations. However, whatever one does, one should be obsessed with
the concerns of the life Hereafter. Allah Almighty, it is hoped, will be kind in
forgiving our minor blemishes.