Not only is it unbiblical to pray to the dead, but we believe that it is also wrong to pray for the dead. There are several Protestant objections to praying for the dead. The most important ones are the following:

Praying for the dead contradicts the separation of death. The Bible speaks of death as separating the living from the departed. Paul speaks of death as “departure” from earth and being with Christ (Phil. 1:23; cf. 2 Tim. 4:6). It is when we “leave the body” (2 Cor. 5:7). Luke 16:26 speaks of a “great chasm” between the living and the dead. Paul speaks of death separating loved ones until they are reunited at the resurrection (1 Thess. 4:13–18). In all of Scripture death is a veil that seals off the living from the dead. Any attempted contacts with the dead are not only futile but forbidden (Deut. 18:11) because of the possibility of demonic deception (cf. 1 Tim. 4:1).

Praying for the dead contradicts the example of David. When David’s baby was alive but seriously ill he prayed for it fervently. However, when the baby died he ceased praying for it immediately.48 When asked why, he replied, “While the child was living, I fasted and wept, thinking, ‘Perhaps the LORD will grant me the child’s life.’ But now he is dead. Why should I fast? Can I bring him back again? I shall go to be with him, but he will not return to me” (2 Sam. 12:22–23). It is clear that David, who as a prophet of God claimed that “the spirit of the LORD spoke through me” (2 Sam. 23:2), believed that prayers for the dead were ineffective. For if he believed that any prayer for the dead was effective, he certainly would have attempted it in his most desperate hour. In fact, in all of his many spiritual writings in the Psalms about how to communicate with God David never once even suggested that we pray for the dead.

Praying for the dead contradicts the example of Jesus. When Jesus lost his close friend Lazarus by death he never prayed to God for him.49 He simply resurrected him with the command “Lazarus, come forth!” Rather than pray for the dead, Jesus prayed for the living. At Lazarus’s graveside Jesus prayed, “Father, I thank you for hearing me. I know that you always hear me; but because of the crowd here I have said this, that they may believe that you sent me” (John 11:41–42). Ironically, many reverse this by weeping for the living who stray and praying for the dead, while Jesus wept for the dead (John 11:35) and prayed for the living (11:41–42). The practice of praying for the dead is not the only time that humanly initiated religious practice has made void the teaching of Sacred Scripture (cf. Matt. 15:6).

Praying for the dead contradicts the sacrifice of Christ. As we have already noted, the whole idea that our prayers or works can do anything on behalf of the dead is contrary to the all-sufficiency of the completed work of Christ on the Cross. His mediation and intercession for them (1 John 2:1–2) are more than sufficient. When Jesus died and rose again the work of salvation was “finished” (John 19:30; cf. 17:4; Heb. 10:14). When he purged our sins he “took his seat” at the right hand of God (Heb. 1:3) since there was absolutely nothing more to do for our salvation. The whole concept of praying for the dead “that they might be freed from sin” is an insult to the finished work of Christ, “who freed us from our sins by his blood” (Rev. 1:5). Jesus not only obtained salvation from all our sins at one time but, as our great high priest (Heb. 7), he alone implements it for all time (see chaps. 12 and 13)

Norman L. Geisler and Ralph E. MacKenzie, Roman Catholics and Evangelicals: Agreements and Differences (Grand Rapids, MI: Baker Books, 1995), 353–354.