海内存知己，天涯若比邻。
Within the four seas, all are brothers; even at the ends of the earth, we are like neighbors.
—— 王勃
Source: 送杜少府之任蜀州(Seeing Off Du Shaofu)
Background
This verse is from Wang Bo's "Farewell to Du Shaofu on His Way to Shuzhou," written when bidding farewell to a friend. It expresses the profound sentiment that true friendship is not limited by distance.
Interpretation
True friendship can transcend spatial barriers. Even if friends are at opposite ends of the world, as long as their hearts are connected, they feel as close as neighbors. This reflects the preciousness and eternity of friendship.