Whether schism is a graver sin than unbelief?

❌ Objection 1 : It would seem that schism is a graver sin than unbelief. For the graver sin meets with a graver punishment, according to Dt. 25:2: "According to the measure of the sin shall the measure also of the stripes be." Now we find the sin of schism punished more severely than even the sin of unbelief or idolatry: for we read (Ex. 32:28) that some were slain by the swords of their fellow men on account of idolatry: whereas of the sin of schism we read (Num. 16:30): "If the Lord do a new thing, and the earth opening her mouth swallow them down, and all things that belong to them, and they go down alive into hell, you shall know that they have blasphemed the Lord God." Moreover the ten tribes who were guilty of schism in revolting from the rule of David were most severely punished (4 Kgs. 17). Therefore the sin of schism is graver than the sin of unbelief.

❌ Objection 2 : Further, "The good of the multitude is greater and more godlike than the good of the individual," as the Philosopher states (Ethic. i, 2). Now schism is opposed to the good of the multitude, namely, ecclesiastical unity, whereas unbelief is contrary to the particular good of one man, namely the faith of an individual. Therefore it seems that schism is a graver sin than unbelief.

❌ Objection 3 : Further, a greater good is opposed to a greater evil, according to the Philosopher (Ethic. viii, 10). Now schism is opposed to charity, which is a greater virtue than faith to which unbelief is opposed, as shown above (Question [10], Article [2]; Question [23], Article [6]). Therefore schism is a graver sin than unbelief.