John 6:64

some of you that believe not There were some of those who followed Him and called themselves His disciples, who still did not believe on Him. The better order is, there are of you some.

knew from the beginning It is impossible to fix the exact limits of this; the meaning of -the beginning" must depend on the context (see on John 1:1). Here the most natural limit is -knew from the beginning of their discipleship," when they first became His followers. Comp. John 2:24-25.

who should betray him Or, who it was that should betray Him. To ask, -Why then did Jesus choose Judas as an Apostle?" is to ask in a special instance for an answer to the insoluble enigma -Why does Omniscience allow wicked persons to be born? Why does Omnipotence allow evil to exist?" The tares once sown among the wheat, both must -grow together till the harvest," and share sunshine and rain alike.