Malachi 2:10 (NASB): Do we not all have one father? Has not one God created us? Why do we deal treacherously each against his brother so as to profane the covenant of our fathers?
I find it interesting that the NASB and NRSV do not capitalize "father," indicating they they interpret "father" as a reference to Adam. The NIV does capitalize it as a reference to God. Because the concept of God as Father is rather rare in the Old Testament, I can see why the NASB and NRSV failed to capitalize it.
I prefer "Father" as a reference to God here. Later in the verse Malachi refers to "the covenant of our fathers," a concept that does not apply to all humanity. To me, this makes the “we” associated with “one Father” appear to stand in subtle contrast with the “us” associated with the “one God” who created us.
We share a bond with all humanity through creation, but knowing God as Father is not a universal experience. Only the people who have joined God in covenant will know and understand the more intimate relationship with God as Father.
Part of our task as children of the Heavenly Father is to introduce those created in the image of God to the Father God. To me that is the heart of the mission of the church.