The Baal Shem Tov used the following teaching of Ramban to illuminate the inner meaning of Deut. 1:17 – that only by detaching yourself emotionally from something, removing the desire that can result from doing that action, can we present G-d with an open heart, our query whether to do it or not.
“Whenever there are various possible options of how to go about doing something, and you are in doubt as to which is the best way, or if you are in doubt as to which is the best way, or if you are in doubt whether or not doing it is at all G-d’s will, in which case it should be done, or it is against His will, in which case you should not, you must first detach yourself all personal gain or honour you may derive from this action, and only then can you objectively weigh the options; For anything from which one derives personal gain, one will search to find some way to permit even the forbidden. But if you do as said, G-d will guide you to the truth and you can feel secure that you are doing the right thing.”
(Keser Shem Tov, Ch. 6.)