Why was the first man immediately declared to be from the tribe of Dan, but the second man needed to be investigated in order to verify that he was from the tribe of Zevulun?
A certain man used to say “Judge my case”. (Whenever
he did business with someone he always said “come for a judgement”, and
he would never listen to anyone but a judge.) They said:
proves that he is descended from the tribe of Dan, for it is written
“Dan shall judge his people, like one of the tribes of Yisrael”
A certain man used to go about saying “By the seashore I will set up palaces”. (“If I had palaces to build I would build them only by the seashore”, and he would constantly praise the seashore.) An alternative text - “By the seashore thorn-bushes are fir-trees”. (He praised the seashore by constantly saying “the thorn-bushes by the seashore are (as big as) fir-trees elsewhere”.) They investigated and found that he was descended from Zevulun, for it is written “Zevulun shall dwell by the sea shore” (Bereishis 49:13).
An explanation as to why in the first case they immediately said that he came from the tribe of Dan, but in the second case they needed to investigate in order to verify that he came from the tribe of Zevulun, can be found here.