It is possible to sin against God, or sin against people, unintentionally. It is even possible to commit an egregious sin without meaning to. I did it myself recently. I won’t go into detail about it, but rather suggest a few things related to unintentional sin. First consider the Scripture as found in Leviticus… (This is an important section of Scripture to read!)
4:1 And the Lord spoke to Moses, saying, 2 “Speak to the people of Israel, saying, If anyone sins unintentionally in any of the Lord’s commandments about things not to be done, and does any one of them… 3 Then he shall offer for the sin that he has committed a bull from the herd without blemish to the Lord for a sin offering. 4 He shall bring the bull to the entrance of the tent of meeting before the Lord and lay his hand on the head of the bull and kill the bull before the Lord.
4:13 If the whole congregation of Israel sins unintentionally and the thing is hidden from the eyes of the assembly, and they do any one of the things that by the Lord’s commandments ought not to be done, and they realize their guilt, 14 when the sin which they have committed becomes known, the assembly shall offer a bull from the herd for a sin offering and bring it in front of the tent of meeting. 15 And the elders of the congregation shall lay their hands on the head of the bull before the Lord, and the bull shall be killed before the Lord.
4:22 When a leader sins, doing unintentionally any one of all the things that by the commandments of the Lord his God ought not to be done, and realizes his guilt, 23 or the sin which he has committed is made known to him, he shall bring as his offering a goat, a male without blemish, 24 and shall lay his hand on the head of the goat and kill it in the place where they kill the burnt offering before the Lord; it is a sin offering.
4:26 So the priest shall make atonement for him for his sin, and he shall be forgiven.
One of the reasons Jesus said what is recorded in Mt 18:15 is unintentional sin… “If your brother sins against you, go and tell him his fault, between you and him alone. If he listens to you, you have gained your brother.” It is possible for a person to sin AND NOT REALIZE IT. Therefore…
1. Ask God to examine your heart and reveal to you how you have unintentionally sinned against Him. Trust me, we both have done it. As it is written…
Ps 139:23 Search me, O God, and know my heart! Try me and know my thoughts! 24 And see if there be any grievous way in me, and lead me in the way everlasting!
1 Cor 11:28 Let a person examine himself, then, and so eat of the bread and drink of the cup. 29 For anyone who eats and drinks without discerning the body eats and drinks judgment on himself. 30 That is why many of you are weak and ill, and some have died. 31 But if we judged ourselves truly, we would not be judged. 32 But when we are judged by the Lord, we are disciplined so that we may not be condemned along with the world.
2 Cor 13:5 Examine yourselves, to see whether you are in the faith. Test yourselves. Or do you not realize this about yourselves, that Jesus Christ is in you?—unless indeed you fail to meet the test!
2. If someone sins against you, consider they may be unaware. You have the responsibility to talk to them yourself… before you discuss it with anyone else… just between you and them.
3. If someone has the courage to speak the truth to you in love about how you sinned against them… A) Do not brush off what they tell you as minor or meaningless, B) Do whatever it takes to make things right with them, C) Be gracious and merciful toward the individual because one day you will be in their position.