"After these things the word of the Lord came unto Abram in a vision, saying, Fear not, Abram: I am thy shield, and thy exceeding great reward." (Genesis 15:1)
This is the first of the great "I am's" of Scripture, and it was given to Father Abraham at a time of both great victory and great despondence. The Lord had enabled Abraham's little army to vanquish a much larger Amorite host, but then, still childless, he was suddenly overwhelmed by his loneliness and vulnerability in an alien land.
Then Jesus came! When Christ much later affirmed His eternal self-existence to the Pharisees ("I am," He had said), He claimed that Abraham had seen His day, and rejoiced (John 8:56). This experience, recorded early in Genesis, was, no doubt, that great occasion. As the living Word (John 1:1) by whom all things were made (v. 3), He assured Abram that He, Himself, would provide all needed protection ("thy shield") and all needed blessing ("exceeding great reward"). And then it was that "he believed in the LORD; and he counted it to him for righteousness" (Genesis 15:6). The Lord Jesus Christ, the eternal existing Creator and Redeemer of all things is no less able today than then to be our protection--and our provision, as well.
Note also that it was the Word of the Lord which came to Abram in a vision. This is the first use of the Hebrew word dabar in Scripture to mean "word," and here it is the Word of God personified. This still further identifies the vision with the pre-incarnate Christ, who would eventually become God's incarnate Word (John 1:1, 14).
Thus, as to Abram, God says: "Fear not!" Adam, indeed, was justifiably afraid when he heard the voice of the Lord (Genesis 3:10), for he had only a fig leaf for a covering. But, like Abram, we have a strong shield, which is none other than the Lord Himself. HMM