Strength and Courage

Hi,
I am writing a book where one of the characters likes Latin and he is looking into creating a motto for his group. The motto would be "Strenght and Courage" . I have searched in google (needless to say, I don't know Latin) and I found both "Vires et Animus" and "Vires et Animis". Do you know if any of those is correct?
Any guidance or help would be appreciated Thanks!