Leviticus 15:3

And this shall be his uncleanness in his issue: whether his flesh run with his issue, or his flesh be stopped from his issue, it is his uncleanness.

Cross-reference

Leviticus 22:4 explicitly repeats that a priest with a discharge cannot eat holy things — directly applying the same rule from Lev 15:3 to clergy.

Leviticus 7:20 shows that uncleanness from discharge (as in Lev 15:3) bars one from eating holy sacrifices — a direct legal application.