What does the word supplication mean?

What does the Bible teach concerning slavery and servanthood? Is it always considered an ungodly practice or are there situations where servanthood is scriptural?

How was a covenant sealed in the Old Testament? Between two different tribes or God and Abraham? Covenants can be made between two different men or entities (as nations) or between God and man.

Bible sacrifices can be placed into several categories: Old Testament animal sacrifices, the sacrifice of Jesus Christ on the cross, and the spiritual sacrifices made by New Testament believers.

Romans 1:28 says, "And even as they did not like to retain God in their knowledge, God gave them over to a reprobate mind, to do those things which are not convenient;" My conclusion has been that God gave them over to a reprobate mind for the destruction of the flesh. What is your thought here?

Can a Christian be turned over to a reprobate mind? I just wonder because there are some people who seem to fall away from God and never desire to go back.

The Bible says that if any have not the spirit of Christ, he is none of His. In the Old Testament, the spirit of God would come upon a man and leave him. How can an Old Testament person be regenerated by the Spirit if this is so?

After the tribulation, will those who survived enter the kingdom in their human bodies? During the kingdom will there be sin on earth?

The Bible deals with the Old and the New Covenant. What is the difference between the two? Who did God make the covenants with?

Where in the Old Testament is the new birth described in such detail that Jesus could have assumed Nicodemus should know about it?