To reveal the size of his love for us, he paid the cost of the revelation out of his own pocket. He paid the cost not from his unlimited divine resources. He paid the cost from his limited human resources. He paid them all for us. He kept not a penny for himself. He has never paid more for anything else.
His willingness to pay everything he owned for us tells us that there is nothing he would not do for our salvation.
The size of his love for us is proportional to the cost that he paid.