To know whether Jesus was without sin, we have to look to the Bible, which defines sin.
First, let us look at some of the definitions of sin from the Bible.
In the Old Testament, it was defined as doing what is forbidden by God.
“Say to the Israelites: ‘When anyone sins unintentionally and does what is forbidden in any of the LORD’s commands-
Suffice it to say that the books of Exodus, Leviticus, Numbers, Deuteronomy have about 613 commands the people of Israel were to follow, showing what God likes and dislikes. I say about, because there is some discussion as the exact number, but this is the number I have heard the most often. Some of these rules were ceremonial, and some were moral.
Let’s look at some of the things Jesus called sin (cp. Matthew 19:18).
19 You know the commandments: ‘Do not murder, do not commit adultery, do not steal, do not give false testimony, do not defraud, honor your father and mother.’”
Jesus told the people who were challenging him because they did not understand what He said,
45 Yet because I tell the truth, you do not believe me! 46 Can any of you prove me guilty of sin? If I am telling the truth, why don’t you believe me?
They could not prove Jesus guilty of sin, because He was NOT guilty of sin.
In fact, Jesus did what God wanted.
If you obey my commands, you will remain in my love, just as I have obeyed my Father’s commands and remain in his love.
In fact, what ever is not from faith is sin.
everything that does not come from faith is sin.
We can see the fact that Christ is sinless easier when we look at what Paul wrote concerning Christ, in 2 Corinthians 5:20-21,
20 We are therefore Christ’s ambassadors, as though God were making his appeal through us. We implore you on Christ’s behalf: Be reconciled to God. 21 God made him who had no sin to be sin for us, so that in him we might become the righteousness of God.
So then, If Christ was without sin, this begs the question, was Jesus the Christ, the Messiah? Jesus Himself said that He was in Mark 14:61-62:
61 But Jesus remained silent and gave no answer. Again the high priest asked him, “Are you the Christ, the Son of the Blessed One?” 62 “I am,” said Jesus. “And you will see the Son of Man sitting at the right hand of the Mighty One and coming on the clouds of heaven.”
We can see in Hebrews that Jesus is our sinless High Priest who faced and overcame temptation, and we can approach the throne of God to receive mercy and find grace when we need it.
14 Therefore, since we have a great high priest who has gone through the heavens, Jesus the Son of God, let us hold firmly to the faith we profess. 15 For we do not have a high priest who is unable to sympathize with our weaknesses, but we have one who has been tempted in every way, just as we are – yet was without sin. 16 Let us then approach the throne of grace with confidence, so that we may receive mercy and find grace to help us in our time of need.
In fact, Jesus Christ was without sin, and we are to follow His example and not sin when we suffer unjustly:
1 Peter 2:19-25
19 For it is commendable if a man bears up under the pain of unjust suffering because he is conscious of God. 20 But how is it to your credit if you receive a beating for doing wrong and endure it? But if you suffer for doing good and you endure it, this is commendable before God. 21To this you were called, because Christ suffered for you, leaving you an example, that you should follow in his steps. 22 “He committed no sin, and no deceit was found in his mouth.” 23 When they hurled their insults at him, he did not retaliate; when he suffered, he made no threats. Instead, he entrusted himself to him who judges justly. 24 He himself bore our sins in his body on the tree, so that we might die to sins and live for righteousness; by his wounds you have been healed. 25 For you were like sheep going astray, but now you have returned to the Shepherd and Overseer of your souls.
So yes, Jesus Christ was without sin. He faced temptation and overcame them, without sinning. He is our High Priest in heaven. He is the Son of God. Because of His sinless life, and the love God, we can approach the throne of God directly.