In the most significant battle during the time of Abu Bakr رضي الله عنه, the battle against Musaylamah al-Kadhdhab, surely the Muslims could have expected Divine support to defeat the false prophet and his forces. Yet Abu Bakr ordered Ikrimah not to enter combat with the kuffar precisely because the size of Ikrimah’s battalion was too small. Abu Bakr ordered him to wait for reinforcements; I don’t think anyone would claim that this order implies a flaw in the ‘Aqeedah of Abu Bakr, or a lack of tawakkul. It is simply the intelligent and responsible decision of a leader who is both sincerely taking care of his people, and genuinely interested in achieving victory.
When Ikrimah, in his enthusiasm to defeat the forces of kufr, chose to attack before the reinforcements arrived, the Believers were indeed driven back, though no one could ever doubt that Allah was on the side of the Mu’mineen.
Now, in that battle, at the Garden of Death, we have an important example of undertaking an outrageously brave action against overwhelming odds, when a single individual, Al-Baraa bin Malik, volunteered to be thrown over the side of the wall directly into the thick of the enemy forces. This was to achieve a particular and highly strategic aim that would be decisive in achieving victory. Yes, it was unrealistic, but the risks were limited and the potential gain outweighed those risks. It was a rational decision based on an objective assessment of the circumstances.