"Last week my pastor preached on Abraham's testing [the sacrifice of Isaac] and I got to wondering. What kind of a God do we 'worship' who'd test someone by demanding the life of another?"
The passage in question is found in Genesis 22.1-18. The story begins, "After these things God tested Abraham. God said to him, 'Abraham!' And he said, 'Here I am.' God said, 'Take your son, your only son Isaac, whom you love, and go to the land of Moriah, and offer him there as a burnt offering on one of the mountains that I shall show you'" (Gen. 22.1-2). The story continues with Abraham obeying God, going to the mountains, and presenting Isaac for slaughter; but just before he does the deed, an angel stops him and Abraham offers a ram in Isaac's place. Because of Abraham's faithfulness God promises Abraham, "Your offspring shall be as numerous as the stars in heaven" (Gen. 22.17). Apparently, God wanted to be sure of Abraham's absolute commitment.
Except God had tested Abraham twice before, both times making the same promise (Gen. 12.1-2; 17.1-11). The first time, Abraham was challenged to leave his home. The second time he was commanded to keep a new covenantcircumcision. On both of these occasions God promised Abraham he would become the founder of a great nation. And then, in the current scenario, God challenges Abraham yet again, this time advocating child sacrifice.
What kind of God is this?
Is this the same God as today?
Yes. And no. God hasn't changed; the God of love, compassion, mercy, and justice is the same God of the Old Testament who seemed more interested in snuffing out nations, meting out discipline in anger, and demanding sacrifice. It isn't God who has changed, it's our understanding of God that has changed.
In the early days of the Hebrews, it is apparent that child/human sacrifice was unfortunately common (cf. Leviticus 27.28-29; Judges 11.30-39) and the story of Abraham and Isaac is located in this setting. The understanding of the deity during this time was of a God who literally pulled the strings of all good and evil occurring on the earth; thus, there was a felt need for sacrifices to appease the anger of the deity (Exodus 32.30).
As time passed, the notion of human sacrifice became abhorrent and laws were recorded (Deuteronomy 18.10) to put an end to these acts. This period of time likely corrosponds to the monarchy beginning with King Saul in 1020 BCE, though it could have been as late as during King Josiah's reign in 640 BCE. However, the need for sacrifices to appease the deity didn't diminish and animal sacrifices flourished during this period.
Even later, however, the Israelite understanding of God changed dramatically. Suddenly, toward the end of the Babylonian exile (538 BCE), the realization came about that God didn't cause all the evil in the world. During this period the personification of evil was cast into the personage of Satan and God was understood more fully as compassionate, merciful, and good. This gave rise to the notion that God wasn't particularly interested in sacrifice at all, preferring instead purity in heart of the faithful (Psalm 51.16-17; Hosea 6.6).
The story of Abraham and Isaac is one of the oldest in the scriptures and reflects the earliest period of the Hebrew faitha time in which human sacrifice was not uncommon (note: there are accounts of this story wherein Abraham actually accomplishes the sacrifice as commanded). Likely, this story exists in its present form not to show God as a testing, demanding, demeaning God, but rather as an etiology (a story of origins or explanation) to advocate the end of human sacrifice.
So, what kind of God do we worship? One who has from the beginning been progressively revealed and profoundly misunderstood, defined and then reduced to our own understanding and level of comfortability. We actually know little about God, except what God chooses to reveal. And God, as revealed in Jesus Christ, is love, compassion, and merciful and as such desires primarily the sacrifice of ourselves in service one to another in the name of God.