Meaning of the word "catch not at the shadow and lose the substance" in English

What does "catch not at the shadow and lose the substance" mean in English? Explore the meaning, pronunciation, and specific usage of this word with Lingoland.

catch not at the shadow and lose the substance

US /kætʃ nɑːt æt ðə ˈʃædoʊ ænd luːz ðə ˈsʌbstəns/
UK /kætʃ nɒt æt ðə ˈʃædəʊ ənd luːz ðə ˈsʌbstəns/
"catch not at the shadow and lose the substance" picture

Idiom

to pursue something illusory or unimportant and as a result lose something of real value

Example:
He quit his stable job for a risky startup that failed, proving you shouldn't catch at the shadow and lose the substance.
By focusing only on social media fame instead of his studies, he is catching at the shadow and losing the substance.