Now, even those who explain Bitachon this way, will qualify things slightly. That is, if a bad occurrence happens, then true, it is a bad occurrence to us. That is, on the revealed plane to us this appears bad. However, on the hidden level it is good. That is, everything that occurs to us G-d intends for our good. At a particular time an event might appear to us to be bad, however, the inner intent is for our good. Sometimes, after the passage of time this inner goodness in the event will become apparent to us, and sometimes it might never become revealed. Still, our Trust in G-d is that G-d is good and that we believe even the revealed bad contains within it a deeper inner good (just not perceivable by human-kind).
This is where things usually end. But the Rebbe asks a further question. What is the simple meaning of Trust? Does not trust mean that we trust that G-d will give us a revealed good? What would the point be in trusting that G-d is going to deliver us a revealed bad, but a concealed good? Something is really not very good until we can really see in a revealed way that the thing is good. Until then, for all practical purposes it is bad. Besides, what would the use of our trust be? Sure we trusted, but we got bad. Our trust had nothing to do with what we got. It was our merits. The same thing would have occurred if we did not trust.
The Rebbe brings a quote from Chovos Levavos. That we trust in G-d, the One who grants good to those who deserve and those who do not deserve.
From this he goes on to point out that Bitachon is not a philosophical principle. It is an avodah (service) in itself. By actively trusting in G-d, we make a change in our situation.
Tefillah (Prayer) & Teshuva (Return to G-d) have the ability to change our situation. Through teshuva we become meritorious. Though before we were not deserving of a certain thing, through teshuva we transform ourselves.
The same is through Bitachon. By trusting in G-d, that G-d is good and that all we receive from G-d is good, we transform ourselves.
If we insisted that the only good is that which is openly revealed to our intellect as good, then we have set ourselves up as gods. We have closed the system and bounded good according to our own dictates. We have left no room in the world for G-d, we want the world to operate according to our dictates, and we leave no room for the possibility that it operates according to higher dictates.
However, by Bitachon in G-d that G-d is the source of all, and thus by definition all is good - we open up the world. We allow ourselves to be open to G-dliness. That ourselves, our situation, and our world operates according to G-dly dictates. And though we might not perceive the goodness of G-d's plan, we have Bitachon that it indeed is good.
This change in our outlook is itself a change in our situation. This Bitachon itself transforms us and makes us worthy. The avodah of Bitachon has the possibility to change our situation so that all that we will receive will indeed be good, and an open clear and indisputable good.
This is what David says in Tehillim: (Psalm 55)
Hashlech al HaShem yavcha, v'hu y'chalklecha, lo yitan l'olam mot l'tadik
Throw on HaShem your needs, and he will support you, he will never allow the tzaddik to fall.
By having an active positive bitachon in HaShem, one changes one's situation and becomes worthy of all good things - even if we don't have the merits otherwise. Just having this Bitachon is itself an avodah which will provide us will all we need, and never let us fall.
This is done by changing Bitachon from a philosophical principle to an avodah. By actually dealing with our day-to-day worldly situation in a manner of Bitachon in HaShem, we transform ourselves and our world.
In Yiddish there is an equivalent statement:
Tracht Gut - Vet Zein Gut.
Think Good, and it will be Good.
This all applies to the individual. An individual might sometimes and at some point in his/her life be less than perfect and perhaps less than totally meritorious. However, when speaking about the totality of the Jewish people, then certainly we are meritorious. Thus certainly via our Bitachon in HaShem, and our trust in our redemption, he will certainly bring Moshiach and the true and final redemption.