A.T. Robertson Commentary John 12:38

"that the word of Isaiah the prophet might be fulfilled, which he spake, Lord, who hath believed our report? And to whom hath the arm of the Lord been revealed?" — John 12:38 (ASV)

That might be fulfilled (ινα πληρωθη). It is usually assumed that ινα here with the first aorist passive subjunctive of πληροω has its full telic force. That is probable as God's design, but it is by no means certain since ινα is used in the N.T. with the idea of result, just as ut in Latin is either purpose or result, as in Joh 6:7; 9:2; 1 Thessalonians 5:4; Galatians 5:17; Romans 11:11 (Robertson, Grammar, p. 998). Paul in Ro 10:16 quotes Isa 53:1 as John does here but without ινα. See Ro 10:16 for discussion of the quotation. The next verse adds strength to the idea of design.