"Be sure you know the condition of your flocks, give careful attention to your herds" (Prov. 27:23).
Identifying and meeting the needs of customers is key to any successful marketing venture. Many years ago Coca-Cola decided to introduce a new Coke. They conducted research among loyal customers to determine if the new taste would be embraced by Coke customers. The evidence proved that the new Coke would be successful. However, what Coke did not realize was the emotional attachment Coke users had to their existing Coke product. It created a massive outpouring of negative publicity when Coke users rebelled against the new Coke. Loyal Coke drinkers may have liked the taste of the new Coke, but they did not want it as a replacement to what they were accustomed to.
The man responsible was fired. It became one of the most famous marketing blunders ever. However, the story does not end here. The company eventually turned a bad situation into a positive one. Coke ended up having two versions of Coke - new and old. The man responsible was rehired and went on to be successful in the company.
Jesus sought to meet the needs of His customer by ministering to their needs as His Heavenly Father revealed them to Him. Their real need for salvation did not get met until Jesus met a physical need that allowed Him to reveal the true need they had. Some of your "customers" have a perceived need for your product. But they also have a spiritual need they may not realize they have. God wants to use you to meet both needs.
That's why it is important for you to know your customer.