John Murray writes concerning Ephesians 1
Here our interest is the expressions ‘being predestined…according to the good pleasure of His will’ (Eph 1:5), ‘the mystery of His will, according to His good pleasure which He purposed in Him’ (vs 9), ‘having been predestined according to the purpose of Him who works all things according to the counsel of His will’ (vs 11). The central issue of the plan of salvation can be staked on these expressions. This latter expression is surely the will unto salvation revealed in the gospel with which the whole passage is concerned. As respects both – predestination and the mystery of His will – it is to trifle with the plain import of the terms, and with the repeated emphasis, to impose upon the terms any determining factor arising from the will of man. If he meant to say anything in these expressions in verses 5, 9 and 11, it is that God’s predestination, and His will to salvation, proceeds from the pure sovereignty and absolute determination of His counsel. It is the unconditioned and unconditional election of God’s grace.