شَهَادَةُ أَحَدِهِمْ means “one person’s testimony”; يَمِينُهُ means “that person’s oath.” The rapid alternation of testimony and oaths depicts a loss of seriousness when making solemn claims.
Witnessing can establish or undermine another person’s rights, so testimony should rest on sound knowledge. An oath is not a conversational decoration or a shortcut to credibility.
Example: Saying “I witnessed it” or invoking an oath when you lack firsthand knowledge is irresponsible.