It is NOT possible to justify the Atlantic Slave Trade using the Whole Bible
Meet Pastor Warren. An influential and learned Christian apologist, here he is making a lengthy speech in which he sets out, with exhaustive chapter-and-verse references, exactly how antebellum slavery was in accordance with God's will, and should be supported by any Bible-believing Christian:
http://civilwarbaptists.com/thisdayinhistory/1861-january-27/
Have a read of it. It's not long, but does make a clear and persuasive case.
A few highlights:
"Slavery forms a vital element of the Divine Revelation to man. Its institution, regulation, and perpetuity, constitute a part of many of the books of the Bible."
"Had God, the Great Law Giver, been opposed to slavery, he would perhaps have said, “thou shalt not hold property in man: thou shalt not enslave thy fellow being, for all men are born free and equal.” Instead of reproving the sin of covetousness, he would have denounced the sin of slavery; but instead of this denunciation, when He became the Ruler of his people, He established, regulated and perpetuated slavery by special enactment, and guaranteed the unmolested rights of masters to their slaves by Constitutional provision."
"The blessed Saviour descended from a slave-holder, Abraham. This “father of the faithful,” held as many bondmen, “born in his house and bought with his money,” as perhaps any slaveholder in the South. When he was chosen out, as the one “in whom all the families of the earth should be blessed,” not a word of Divine disapprobation, on account of his being a slave-holder was uttered. His descendants, the Jews, up to the time of their national dispersion, were as emphatically a slave-holding people as we Georgians are."
"He (Jesus) reproved them for their sins. Calling them the works of the flesh and of the devil. He denounced idolatry, covetousness, adultery, fornification, hypocrisy, and many other sins of less moral turpitude, but never once reproved them for holding slaves; though He alluded to it frequently, yet never with an expression of the slightest disapprobation."