In many books it is stated that the Raychaudhuri equation is a sort of "proof" that in general relativity gravity is attractive. This is done by considering a bundle of geodesics, and proving that under certain reasonable conditions its expansion $\theta$ has a negative time derivative. This implies that a bundle of geodesics tends to converge as time goes on, and hence it would imply that the curvature of spacetime produces an attractive force.
I have a problem with this interpretation, though. A bundle of geodesics implies a bundle of test particles: objects whose gravitational influence can be neglected. The spacetime curvature is supposed to be sourced by some other matter distribution, not by our geodesics. We seem to be proving that test particles are attracted to each other! But that's not what gravity does: test particles should be attracted by matter, not by each other. Am I misunderstanding the interpretation of the Raychaudhuri equation?
In fact, I can think of a situation where gravity could have a diverging effect (please let me know if this part should be a separate question). Consider two neighboring test particles heading in the general direction of a planet, with impact parameters $b$ and $b + \delta b$: one of them will pass closer to the planet than the other. Then the closer particle will be deflected more than the farther particle, so that their trajectories will diverge as they pass near the planet. Does this not contradict the Raychaudhuri equation? Or, if it doesn't, doesn't this example show that gravity can be attractive and yet have a diverging effect?