Set parent of an instantiated object where the object being instantiated is a transform

Hello. I am fairly new to Unity 3D and I am starting a project. The player crafts an item and as soon as it’s crafted, the item falls to the ground. I want to attach a script to that object that OnTriggerEnter it destroys the object that has been created and re-instantiates the object in the hands of the player and when it is instantiated, it sets the hand of the player as the parent of the object. PLEASE TAKE NOTE:

This is my script being attached to the prefab (The object is a knife)

var InventorySystem: Inventory;
var SpawnPosition: Transform;

function Start()
{
	InventorySystem = GameObject.Find("3rd Person Controller").GetComponent(Inventory);
	SpawnPosition = GameObject.Find("AltItemPos").transform;
}

function OnTriggerEnter(Col:Collider)
{
	if (Col.tag == "Player")
	{
		InventorySystem.itemEquipt();
	}
}

And this is the function: itemEquipt() and the variables it uses

var knife: Transform;

function itemEquipt()
{
	Destroy(PickUpScript.gameObject);
	Instantiate(knife, PickUpScript.SpawnPosition.position, PickUpScript.SpawnPosition.rotation);
}

//How do I instantiate it and make it the child of SpawnPosition?

THANK YOU!

var knifePrefab: Object;

function itemEquipt()
{
    Destroy(PickUpScript.gameObject);
    GameObject newKnife = (GameObject)Instantiate(knifePrefab, PickUpScript.SpawnPosition.position, PickUpScript.SpawnPosition.rotation);
    newKnife.transform.parent = PickUpScript.SpawnPosition;
}