John 11:4

Ἀκούσας δὲ ὁ Ἰησοῦς εἶπεν. “And Jesus when He heard said,” i.e., to His disciples. It was not the reply sent to the sisters. “This illness is not to death,” πρὸς θάνατον, death is not the end towards which it is making. But that Jesus knew that death had already taken place (John 11:6 and John 11:17) or was imminent is evident from the following clause, but He knew what He would do (John 6:6) and that death was not to be the final result of this illness. The illness and death were ὑπὲρ τῆς δόξης τοῦ Θεοῦ, for the sake of glorifying God (cf. John 9:3), “gloriae divinae illustrandae causa,” Winer, p. 479. This is further explained in the clause “that the Son of God may be glorified by means of it,” i.e., by means of this illness; cf. John 13:31. “In two ways; because the miracle (1) would lead many to believe that He was the Messiah; (2) would bring about His death. Δοξάζεσθαι is a frequent expression of this Gospel for Christ's death regarded as the mode of His return to glory (John 7:39; John 12:16; John 13:31), and this glorification of the Son involves the glory of the Father (John 5:23; John 10:30-38).” Plummer, Bengel.