A motif is a topic or idea that appears consistently throughout a literary work. Usually, this is abstract.
For instance:
love, greed, hate, hope, peace etc.
A theme is an opinion or comment on the motif that the author is trying to express and can be proven through literary devices in the work. Sometimes, the theme can be a connection between two motifs.
For instance:
Family can be made.
People can rise out of the situations they were born into.
Stereotypes can be broken.
Seeking revenge can lead to one's downfall.