Where in the Bible does it support the belief in predestination?
There are several texts usually thought to support the notion of predestination, mostly in the Pauline epistles. For example, Ephesians 1:3-14 is thought to suggest this idea, as does Romans 8:29-30. On closer inspection, the former text is speaking about Christ being the one destined by God for various things, and those who are ‘in Christ’ (Christians) receiving benefits. One is said to enter the body of Christ by grace through faith, according to the same text. Romans 8:29-30 stresses that God has destined those who are in Christ to be conformed to his image. That is the believers’ destination. This, however, does not mean that a person can’t derail this process. Apostasy is a real possibility referred to in a host of texts (see, for example, 1 John 5:16-17; Hebrews 6:4-5). What the predestination texts suggest is that God has a plan and is executing it, and unless the believer opts out, this plan will come to fruition.
—Ben Witherington III