First of all, "digging three feet" means that a person works hard and seeks good results with diligent actions. The "good" here can refer to a bumper harvest or a successful goal.
Secondly, "striving for the first place" means that through unremitting efforts, this person finally succeeded and won the first prize.
Then "meeting a bosom friend" describes meeting unexpectedly. This person meets a person who knows and appreciates him, and that is his confidant. This meeting may be accidental, but it gave him new opportunities and motivation.
Finally, "Meet in the sky and join hands" expresses the story of their common success. Climb high together and open up a broader world.
Generally speaking, this poem encourages people to work hard, pursue success, and meet bosom friends in the process of success to achieve greater goals together.