Genesis 28:22 - Jacob's vow with God.

This stone, which I have set for a pillar, shall be God's house: and of all that thou shalt give me I will surely give the tenth unto thee.

After God blesses Jacob with prosperity and a large family, Jacob remembers his vow with God and returns to this stone and builds an altar (Genesis 35:7).

Genesis 28:17 - On holy ground.

And he was afraid, and said, How dreadful is this place! this is none other but the house of God, and this is the gate of heaven.

This place is holy ground that Jacob was lying on when he dreamt his vision. Just like Moses at the burning bush (Exodus 3:5-6), Jacob became afraid when he realized that he was in the presence of God. Joshua too found himself standing on holy ground when the captain of the Lord's army appeared before him, just before the fall of Jericho (Joshua 5:15).