Shri Vallabh has advised the Vaishnavas that -"We must serve Shriji with the wealth that is achieved without much effort or attachment" (Praptam sevet nirmamah).
It is a well known fact that we get results if we have faith.The Chatak bird drinks water in a specific Nakshatra (a term in Indian astrology) only.He has faith that it shall surely rain in this Nakshatra.it is said that this thing does happen,rain does come in this Nakshatra without fail.
The opposite of faith is not to have faith.It is the biggest hurdle in achieveing results.This can be shown with an example from the Ramayana.The Asuras of Lanka had tied Shri Hanumanji with the help of the Brahmastra.But they did not have enough faith on the Brahmastra and wanted to bind Shri Hanumanji in a better way.So they tied Shri Hanumanji with heavy chains and Shri Hanumanji escaped.This shows that if you don't have faith on anything or anybody then you cannot achieve your goals.
The sentence Praptam Sevet nirmamah is the test of our faith in Shriji.The meaning of the sentence "Whatever is achieved with the grace of God" is that our efforts should not be towards achieveing material goals but sewa must have greater importance in our lives.We must have faith that Shriji will do whatever is best for us.Also,we must not have the feeling that "all these things are mine",but should always remember that we are mere trustees of whatever we have in this world,in fact all the things we possess belong to Shriji and he has given them to us which is his kripa (grace).
Faith has another aspect also and that is our feeling that Shriji will accept all our offerings.Shriji always accepts whatever we offer to him if the offering has been achieved without much effort.The only condition attached to it is that we must be fully dedicated in whatever we do in our sewa.What else,barring our full dedication,can we offer to Shriji who is the Lord of the whole world!!
Shri Gadadhardas Purohit used to do sewa and live on the offerings that his Yajmans gave to him.He never used to go out in search of anything.One day as no one came to his house he offered only water in all the bhogs to Shri Madanmohanji.Here we see the example of both the types of confidence that we have discussed.Faith on the Lord and confidence on his Anugraha (grace).Here Shri Gadadhardas could have done sewa by borrowing from someone but in such a case the sewa would not have by him but by whoever he had borrowed from.How could Shri Madanmohanji accept the offerings of any other being?!!
Shriji only wants full dedication on our part.That is why the principle is that we must do sewa with whatever we achieve without much effort.