The personal form of God enters our hearts through two ways- first is by making us hear about Him and secondly by making us see His images.
Listening to His attributes, stories of His mercy and pastimes develops a sort of fondness for Him causing us to know more and more. This is called guna- aaskti (addiction with His attributes). Looking at His pictures, statues then enables us to feel them as His living figures. The devotee becomes so much obsessed (aasakt) with His beauty that he gets to see it everywhere around. So Shravan bhakti has been given the first preference as directly looking at Him may carry only a short-term impact while aaskati developed through listening is much stronger. Devi Rukamani fell in love with Lord Krishna without seeing Him and Afghani poet, Raskhan too became anxious to meet Shri Banke Bihari just after hearing about Him.