It is important to precisely define what the question means by the term “The Bible”. The Old Testament is of purely Jewish extraction and it does sanction slavery. However, the big difference between this Jewish form of slavery and Western or Islamic slavery was that it was not justified on the grounds of race, or religious affiliation but on the grounds of economic and political factors. A person could become a slave due to being unable to repay his debts or because his nation had lost a war against the Jews. Therefore, even a Jew could become s slave. Physical abuse was forbidden.
The New Testament on the other hand, is the written record of oral traditions that were transferred by the first Christian Apostles of Jewish extraction, sometimes long after their death. These are the answers on the excerpts you have provided:
1 Corinthians 7:20 -22: written by Saint Paul, a Jew with Roman citizenship. Saint Paul was a man of his time and he accepted slavery as part of the social structure of his time, based on the Christian principle of “giving to Caesar what is Caesar’s and giving to God what is God’s”. However, he also expresses that such acceptance does not mean that God sanctions slavery as the following verse indicates; “21 Were you a slave when you were called? Don’t let it trouble you—although if you can gain your freedom, do so. 22 For the one who was a slave when called to faith in the Lord is the Lord’s freed person; similarly, the one who was free when called is Christ’s slave. 23 You were bought at a price; do not become slaves of human beings.”
The next verse, 1 Corinthians 12:13, also follows the same logic of resignation before earthly ways and hope for future spiritual deliverance.
Galatians 3:28; also written by Saint Paul, this verse clearly establishes full equality between free persons and slaves.
Philemon 1:16; this Epistle was co-authored by Saint Paul and Timothy. This Epistle deals with a slave named Onesimus, who allegedly stole some money from Philemon, his Christian master and fled. Saint Paul sheltered him and convinced him to return to his master and gave him a letter for the latter. The epistle asks Philemon to forgive Onesimus and to no longer consider him a slave, implicitly asking for his manumission.
Ephesians 6:5-9; written by a later Christian scholar, based on an oral account by Saint Paul. This series of verses clearly ask that Christian slaves be gentle and obedient to their masters and in turn ask masters that they behave towards their slaves in exactly the same way! The letter actually asks masters to serve their slaves and ends with a warning that God above is the master of all mortals.
Colossians 3:22; written by an anonymous assistant of Apostle Paul, it basically makes part of a series of instructions for Christian households. The verses do imply that slaves are considered as part of the household. It is evident that because these recommendations are addressed to Christian households, they intend to ensure their harmony and consequently their good reputation in the community. Saint Paul accepted slavery as an inevitable reality of the time but made sure to convey the implicit message that there was no fundamental difference between slaves and their masters.
Colossians 4:1. This particular verse conveys the idea of an existing hierarchy where slaves have masters above them, who in turn are slaves of those who are above them, all the way up to God. Again, the notion of slavery is implicitly Christianized, gradually erasing slave-master differences and turning all Christians into servants of God.