The Heidelberg Catechism Part II: Deliverance God the Son, Part 3 Lord’s Day 13
Question 33: Why is He called God’s “only begotten Son” when we also are God’s children?
Answer 33: Because Christ alone is the eternal, natural Son of God.  We, however, are adopted children of God – adopted by grace through Christ. 
 John 1:1-3 NKJV In the beginning was the Word, and the Word was with God, and the Word was God. (2) He was in the beginning with God. (3) All things were made through Him, and without Him nothing was made that was made.
John 1:14 NKJV And the Word became flesh and dwelt among us, and we beheld His glory, the glory as of the only begotten of the Father, full of grace and truth.
John 1:18 NKJV No one has seen God at any time. The only begotten Son, who is in the bosom of the Father, He has declared Him.
Hebrews Chapter 1: (see Hebrews Chapter 1 in your Bible)
 John 1:12 NKJV But as many as received Him, to them He gave the right to become children of God, to those who believe in His name:
Romans 8:14-17 NKJV For as many as are led by the Spirit of God, these are sons of God. (15) For you did not receive the spirit of bondage again to fear, but you received the Spirit of adoption by whom we cry out, "Abba, Father." (16) The Spirit Himself bears witness with our spirit that we are children of God, (17) and if children, then heirs—heirs of God and joint heirs with Christ, if indeed we suffer with Him, that we may also be glorified together.
Ephesians 5:5-6 NKJV For this you know, that no fornicator, unclean person, nor covetous man, who is an idolater, has any inheritance in the kingdom of Christ and God. (6) Let no one deceive you with empty words, for because of these things the wrath of God comes upon the sons of disobedience.
Q 34: Why do you call Him “our Lord”?
A 34: Because – not with gold or silver, but with his precious blood  – He has set us free from sin and from the tyranny of the devil,  and has bought us, body and soul, to be His very own. 
 1 Peter 1:18-19 NKJV knowing that you were not redeemed with corruptible things, like silver or gold, from your aimless conduct received by tradition from your fathers, (19) but with the precious blood of Christ, as of a lamb without blemish and without spot.
 Colossians 1:13-14 NKJV He has delivered us from the power of darkness and conveyed us into the kingdom of the Son of His love, (14) in whom we have redemption through His blood, the forgiveness of sins.
Hebrews 2:14-15 NKJV Inasmuch then as the children have partaken of flesh and blood, He Himself likewise shared in the same, that through death He might destroy him who had the power of death, that is, the devil, (15) and release those who through fear of death were all their lifetime subject to bondage.
 1 Corinthians 6:20 NKJV For you were bought at a price; therefore glorify God in your body and in your spirit, which are God's.
1 Timothy 2:5-6 NKJV For there is one God and one Mediator between God and men, the Man Christ Jesus, (6) who gave Himself a ransom for all, to be testified in due time,