In Macbeth, how does Malcolm test Macduff's loyalty?
I had to whittle your question down.
Malcolm says to Macduff: “He hath not touched you yet.” Malcolm wonders if Macduff is working with Macbeth. At this point, Malcolm’s father has been killed and as far as they both know, Macbeth has not harmed Macduff or any of his family. Malcolm also questioned how Macduff could leave his family so quickly.
Perchance even there where I did find my doubts.
Why in that rawness left you wife and child.
Malcolm suspects that Macduff might be on Macbeth’s side since he felt confident in leaving his family in Scotland. Macduff, in fact, left with Malcolm to secure an army and to support Malcolm as the rightful heir to the throne. Macduff has been consistently loyal to Duncan and Malcolm. Macduff leaving his family was perhaps foolish but not malicious.
After Macduff effusively praises Duncan and despises a Scotland ruled by Macbeth, Malcolm begins to trust his loyalty. This trust is quickly confirmed when Ross tells them Macduff’s family has been slaughtered.