"All Old Testament believers (e.g. Enoch, Noah, Abraham, Moses, David, etc.) who died before Christ were saved in Christ by faith (e.g. John 5:46; 1 Pet. 1:10-12), just as believers are saved today. The sacrifices in the tabernacle were not themselves an effective means of atonement (Heb. 10:1-4; cf. Rom. 8:1-4; Heb. 9:13-14), and by the same reasoning neither were prior sacrifices (e.g. Abraham was counted righteous by God because of his faith, not because he offered sacrifices [Gen. 15:6; Rom. 4:3; Gal. 3:6]). Rather, they pointed to Christ, who was the sufficiency behind those sacrifices (Heb. 9:1-15).Old Testament believers had far less knowledge of Christ than we do (they did not know he was Jesus of Nazareth, for example), but they trusted God and him alone for their salvation (Heb. 11). As Hebrews 11:39-40 teaches, God did not fulfill the ultimate promises to the Old Testament saints before Christ because he wanted to make them perfect with us, the New Testament saints -- and we all still await Christ's return for our final blessings so that all believer (even those yet to come to faith) will be perfected together. In the meantime, Old Testament saints are in heaven (e.g. 2 Kgs. 2:11; Heb. 11:5), as are New Testament saints (Christians) who have died, awaiting the resurrection of their bodies (Matt. 22:31-32 [// Mark 12:26-27; Luke 20:37-38]; 1 Cor. 15; 1 Thess. 4:13-17). While they are in heaven, they are conscious and active (Matt. 17:3 // Mark 9:4; Luke 9:30; compare Rev. 6:9).
Unbelieving Jews and Gentile who lived during the Old Testament era perish for eternity in hell (Matt. 10:15; 11:22,24; John 5:24-29; 2 Pet. 2:4-9)." -- R. McLaughlin
And from the following excellent essay...
"...The Bible affirms directly that the elect were known by God before the foundation of the world and chosen by him in Christ before any one of them was born (Ephesians 1:4). Therefore God bases his blessing on Christ's merits prior to the events taking place in history. Therefore, since sin is only removed by Christ's work, and not by the symbolic representations of the sacrifices (Hebrews 10), we deduce that all believers, Old and New Testament saints, were saved by God's work of grace alone, based upon the completed work of the Messiah, applied to undeserving hearts by the Holy Spirit producing in the person faith, repentance and obedience."
If they were the "elect" from all eternity, why were they (con)damned and sent to hell to begin with?