Ice and iron cannot be welded.

The image of “ice” and “iron” suggests two materials—and by extension two temperaments or principles—that resist fusion. Ice melts under heat; iron requires heat to be forged, yet ice cannot endure the conditions that make welding possible. As a proverb-like statement, the line implies that some combinations (people, values, plans) are structurally incompatible: forcing them together will destroy one element rather than create a durable union. It can be read as counsel about relationships or alliances, warning that apparent complementarity may conceal irreconcilable differences.