Much of God's creation is marked by the number three. This makes sense since God Himself is a trinity. There are three kinds of vegetation: grass, herbs and trees (Genesis 1:11). There are three kinds of lights in the sky: the sun, the moon and the stars (Genesis 1:16). There are three kinds of animals: fish, fowl and land animals. There are three kinds of land animals: cattle, creeping things and beasts (Genesis 1:24). Man has three parts: spirit, soul, and body (1Thessalonians 5:23). There are three basic colors and three states of matter (solid, liquid and gas). If you think about it, you can find other examples.
Of the 17 times the word firmament is used in the Bible, over half (or 9) of the times are found in Genesis One. Firmament means an expanse or expansion of space and it refers to the expansion of space between the earth and God's heavenly abode. It is bound by the waters above and the waters below (Genesis 1:6-8). This explains why there are "waters that be above the heavens" (Psalm 148:4). Of the three heavens indicated in 2Corinthians 12:2, the firmament includes the first two heavens while the third heaven refers to God's dwelling place. The first heaven is the "open firmament of heaven" where the birds fly (Genesis 1:20). The second heaven is "firmament of the heaven" where the planets and stars reside (Genesis 1:14-15). As known to anyone who has considered the heavens as the work of God's finger (Psalm 8:3), the firmament exalts God. As the psalmist proclaims in Psalm 19:1, "The heavens declare the glory of God; and the firmament sheweth his handywork."
On three different occasions the Apostle Paul admonishes believers to be followers of him (see 1Corinthians 4:6; 1Corinthians 11:1; and Philippians 3:17). With this in mind we ought to preach the gospel which Paul preached. We find this gospel defined in 1Corinthians 15:1-4, where it says the gospel includes the death, burial and resurrection according to the scriptures. Today we are taught by many of the necessity of baptism for salvation. Apparently Paul did not know this for he said, "For Christ sent me not to baptize, but to preach the gospel" (1Corinthians 1:17). Notice that Paul contradicted the gospel and baptism as if they were not the same. If Paul believed that baptism was necessary for salvation, then he was one of the biggest hypocrites ever to walk the face of this earth. He should have been going all over the countryside dunking people in water instead of wasting his time in prison for preaching the gospel.
The following is an excerpt from Soldiers in Training by Brother Daryl Coats.