Both intellectual and physical efforts are equally essential for every single person.
'The 101st hit cracked the rock' – No! This was the impact of the 100 earlier hits, the last one being merely the last straw, the immediate cause.
The extent to which I do Bhakti & Seva and the extent to which I make an effort to behave in righteous way, to that extent more & more good things keep happening in my life.
I attain good bhakti through my good conduct. good bhakti begins to bear good efforts and good efforts, in turn, improve my actions (karma).
Never get scared when faced with a problem. My bhakti grow as big as that of a problem. My efforts should be equally great.