You can use the fact that awk arrays are indexed by strings and the awk built-in variable FILENAME - the name of the current file.

This assumes default field separators, and that blacklist.txt contains one field per line. Adjust according to your needs.

#!/bin/sh

awk '
    {
        if (FILENAME == "blacklist.txt") {
            blacklist[$0] = 1
        }
        else {
            if (blacklist[$4]) {
                print $4, $0
            }
        }
    }
' blacklist.txt -

This can be acomplished using two features of awk:

1. arrays are indexed by strings
2. the built-in variable FILENAME

This script assumes default field separators, and that blacklist.txt contains one field per line. Adjust according to your needs.

#!/bin/sh

awk '
    FILENAME == "blacklist.txt" {
        blacklist[$0] = 1
        next
    }
    blacklist[$4] {
        print $4, $0
    }
' blacklist.txt -