Why do we say that ‘induction always precedes attraction’?

The fact that a charged body attracts light particles can be explained on the basis of induction. Consider, a negatively charged rod is brought near a small piece of metal foil as shown in the fig. below.


The free electrons present in the metal foil are repelled to the end D leaving a positive charge near C. Now, since the positive charge is near to the charged rod as compared to the negative charge, the resultant force in the foil is attractive. Thus, induction always precedes attraction of small particles.