This verse is referring to Isaac. In a short verse, the message points out that even though Isaac was great, he didn't stop there. He became greater. This is what true excellence means. It is not a finite goal. It is an attitude that is continuous and has no end. Regardless of how great a person's accomplishment is, he should view this as step and an example to producing an even greater achievement. Of course, one should be proud of his accomplishments, but, at the same time, when one views a big accomplishment as the end of a path, one ceases to be excellent. The path from that point is downward. Instead, the path must always be upwards, striving to reach an even greater goal.
The man became great. He continued becoming greater until he
was exceedingly great (Genesis chapter 26 verse 13.)
Further inspection of the next Biblical verse (verse 14 in the same chapter) states what Isaac gained - cattle, sheep, etc. numerous possessions. It is the end of that verse (verse 14) that states, "The Phillistines were jealous of him."
How sad that is! Notice that the verse did not state that they were envious of his possessions or his success, but they were envious of him, as a whole. In the end, the Phillistine king, Abimelech chased Isaac away because he and his people couldn't handle such envy and the competition. (Eventually, though, Abimelech relented, apologized, and made a peace pact with Isaac.)
The Phillistines, sadly, did not look as Isaac as a mentor. They could have asked Isaac how he became successful, and perhaps learned from him. Had they done that, perhaps, they would have become a more prosperous people and tribe. Instead, they became a savage, warrior group of people who brutally killed others and prided themselves on their physical strength.
Sadly, the way the Phillistines acted then, is common practice in numerous societies. Envy can be constructive when people use it as a means to learn and emulate someone else's success and moral behavior. Sadly, envy, more often results in distrust, hostility, and often, war.
If you know of someone else who is successful, don't be jealous. Learn from their knowledge. If you ask, they will, most likely tell you. Any truly successful person is smart enough to know that there is enough space in the world for success to be shared without detracting from his own success. If you have achieved greatness, why not make the first step and be a mentor to others?