When you have generated the Bodhimind, the activities or whatever you do this is influenced by the Bodhimind that all becomes the cause for enlightenment. Since all the merits that we earn, all the virtuous actions that we accumulate may not necessary become the cause for enlightenment as I mentioned mostly they are not going to be the cause for enlightenment.
But once the Bodhimind is with you, your activities are influenced by this mind and by the power of this mind all the merits you earn from that moment become the cause for enlightenment. That means, once the merits becomes the cause for enlightenment then you can enjoy the results and enjoy the fruits till you get enlightenment.
Because we might have accumulated a lot of merits but then once they give the good results then they are exhausted no more results will be there. But if your merits are influenced by the Bodhimind then that can never end till enlightenment. Therefore, it is a powerful instrument to accumulate merits.
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http://www.norbucholingcentre.org/downl ... icitta.pdf