Habib `Abdullah bin Husayn bin Tahir (may Allah have mercy upon him and benefit us by him) gives a metaphor for guidance.
“Felicity, guidance and all good attributes are like seeds planted in the heart of the believer. Those that call people to Allah and remind them of Allah and their reminders are like rain. People’s hearts are like the soil. Reminders are directed to the hearts like rain falls upon the soil. If Allah has decreed that it is time for someone to return to Him, the heart will react and submit and follow guidance, just like when rain falls upon fertile soil in which seeds have been planted it yields a good harvest.
Conversely, if the call is directed to hearts which possess no good qualities, it will be like rain falling upon rocky ground. If the call is directed to hearts filled with blameworthy qualities which are destined for wretchedness, they will respond by stubbornly rejecting the call and mocking the callers. This is like rain falling on earth filled with thorn trees. The more the rain falls, the more these trees grow and the more harmful they are. The only way to deal with them is to uproot them and burn them.”