13 When God made his promise to Abraham, since there was no one greater for him to swear by, he swore by himself, 14 saying, “I will surely bless you and give you many descendants.”[d] 15 And so after waiting patiently, Abraham received what was promised.

16 People swear by someone greater than themselves, and the oath confirms what is said and puts an end to all argument. 17 Because God wanted to make the unchanging nature of his purpose very clear to the heirs of what was promised, he confirmed it with an oath. 18 God did this so that, by two unchangeable things in which it is impossible for God to lie, we who have fled to take hold of the hope set before us may be greatly encouraged

Jesus wrote a letter to the church in Revelations 3:20 saying "Here I am! I stand at the door and knock. If anyone hears my voice and opens the door, I will come in and eat with that person, and they with me." To think that this was a letter to the church is a sign that many believers do not know God beyond the church.