Dilige et fac quod vis

Keeping the Law 

Disciples asked the maggid of Zlotchov: "In the Talmud we read that our Father Abraham kept all the laws. How could this be, since they had not yet been given to him?" 

"All that is needful," he said, "is to love God. If you are about to do something and you think it might lessen your love, then you will know it is sin. If you are about to do something and think it will increase your love, you will know that your will is in keeping with the will of God. That is what Abraham did."

Yehiel Mikhal of Zlotchov. in Tales of the Hasidim (Martin Buber ed.), Olga Marx (trad.) Schocken Books (1947)