My daughter likes doing this too (grabbing the bowl/spoon) so I just tell her patiently that I'll help her eat --- I put my hand over hers to guide the spoonful of food into her mouth. This way she still has some level of control but it's not as messy! Fun too :)
That's normal, I guess, for babies who are just recently introduced to solids. Maybe your baby is just curious as to where you get the food he or she is eating. Just keep on feeding and make it interactive. It'll help a lot.