Genesis 22:13

‘And Abraham lifted up his eyes and looked, and behold, a ram caught in the thicket by his horns. And Abraham went and took the ram and offered him up for a burnt offering in the place of his son.'

To us it may seem an afterthought, but to Abraham it is one great swell of praise to Yahweh. Never had he offered a ram with more gratitude and with more praise in his heart. Whatever the normal significance of the burnt offering it is clearly stated that in this particular case it is substitutionary. It replaces his son. The burnt offering was in fact more of a total offering to God of worship and praise and dedication, and it was this for Abraham. But as ever it included the shedding of blood and was thus a reminder that sin produced death, the death of the victim in the place of the guilty one.