*raises hand* I can.
Abraham's whole life is marked by his spirit of trustfulness, his deep faith in creator God. Of him it is recorded that ‘he believed the Lord; and He [the Lord] reckoned it to him as righteousness’ (Gn. 15:6). This text is taken up by New Testament writers, and the fundamental truth it expresses developed more fully.
As Romans 12:3 demonstrates, "God has allotted to each a measure of faith." Humanity has the ability to exercise faith. Faith is an instrument that people may choose to exercise or not to exercise. They may place their faith in something that is true or not true, but the ability itself is God given. Humanity is endowed with it and faith is a uniquely human possibility.
But you asked where did Abraham get his faith from.
Abraham was a descendent of Shem who was a son of Noah. The knowledge of creator God, who saved his ancestors, was passed down to Abraham who exercised his faith with respect to it.
And not to get off on a tangent but people today think of Christianity as an off-shoot of Judaism; however, it's important to remember that the core beliefs of Christians that God would take on flesh, die and rise again were already evident among Abraham’s Horite people (who remembered the ancient promises of God).
The dying and rising of God in terms of the sun’s rising and setting (not to be confused with later pagan mythologies, syncretism, etc...) was present in their culture (noting that they did not worship the sun as the pagans did).
Rather the sun served as the best analogy for the ancient promise of Creator God who made and ultimately ruled over the whole world. Unlike its lesser opposite the moon, the sun makes life possible on earth. It is the great light from which the moon receives its light. In Genesis 1:16, the sun is called the "greater light" and the moon the "lesser light." The sun and the moon were never considered equal among the Horite people who retained this cultural metaphor in rememberance of their creator and His ancient promise.