The monkey usually symbolises the uncontrolled physical mind. In your case he probably wanted to steal the fruits of your spiritual aspiration.

It is the nature of the physical mind not to believe or accept anything that is supraphysical unless it is enlightened and compelled by the light to do it. Do not identify yourself with this mind, do not consider it as yourself but only as an obscure function of Nature. Call down the light into it until it is compelled to believe.

This call for faith, sincerity, surrender is only an invitation to make your co-operation more easily possible. If the physical mind ceases to judge all things including those that it does not know or are beyond it, like the deeper things of the spirit, then it becomes easier for it to receive the Light and know by illumination and experience the things that it does not yet know. If the mental and vital will place themselves in the Divine Hand without reservation, then it is easier for the Power to work and produce tangible effects. If there is resistance, then it is natural that it should take more time and the work should be done from within or, as it might appear, underground so as to prepare the nature and undermine the resistance.