Whether respect of persons is a sin?

Objections

Objection 1 : It would seem that respect of persons is not a sin. For the word "person" includes a reference to personal dignity [*Cf. FP, Question [29], Article [3], ad 2]. Now it belongs to distributive justice to consider personal dignity. Therefore respect of persons is not a sin.
Objection 2 : Further, in human affairs persons are of more importance than things, since things are for the benefit of persons and not conversely. But respect of things is not a sin. Much less, therefore, is respect of persons.
Objection 3 : Further, no injustice or sin can be in God. Yet God seems to respect persons, since of two men circumstanced alike He sometimes upraises one by grace, and leaves the other in sin, according to Mt. 24:40: "Two shall be in a bed [Vulg.: 'field' [*'Bed' is the reading of Lk. 17:34]], one shall be taken, and one shall be left." Therefore respect of persons is not a sin.