Is it a command to seek forgiveness of sin from a brother before worshiping God?

Answer:

"You have heard that the ancients were told, 'You shall not commit murder' and 'Whoever commits murder shall be liable to the court.' But I say to you that everyone who is angry with his brother shall be guilty before the court; and whoever says to his brother, 'You good-for-nothing,' shall be guilty before the supreme court; and whoever says, 'You fool,' shall be guilty enough to go into the fiery hell. Therefore if you are presenting your offering at the altar, and there remember that your brother has something against you, leave your offering there before the altar and go; first be reconciled to your brother, and then come and present your offering" (Matthew 5:21-24).

Some forget that worship is not just between God and me. It also shows fellowship between God, me, and the people I'm worshiping with. Jesus' statements were to an audience that was worshiping under the Old Law, but it remains the same under the New Law. "Is not the cup of blessing which we bless a sharing in the blood of Christ? Is not the bread which we break a sharing in the body of Christ? Since there is one bread, we who are many are one body; for we all partake of the one bread. Look at the nation Israel; are not those who eat the sacrifices sharers in the altar?" (I Corinthians 10:16-18).

"What we have seen and heard we proclaim to you also, so that you too may have fellowship with us; and indeed our fellowship is with the Father, and with His Son Jesus Christ. ... If we say that we have fellowship with Him and yet walk in the darkness, we lie and do not practice the truth; but if we walk in the Light as He Himself is in the Light, we have fellowship with one another, and the blood of Jesus His Son cleanses us from all sin" (I John 1:3, 6-7).

If a brother or sister is mad at me because of something I've done, then that interferes with the fellowship. We are no longer united and that disharmony interferes with our fellowship with God. "There are six things which the LORD hates, yes, seven which are an abomination to Him: ... and one who spreads strife among brothers" (Proverbs 6:16,19).

"The one who says he is in the Light and yet hates his brother is in the darkness until now. The one who loves his brother abides in the Light and there is no cause for stumbling in him. But the one who hates his brother is in the darkness and walks in the darkness, and does not know where he is going because the darkness has blinded his eyes" (I John 2:9-11).

"If someone says, "I love God," and hates his brother, he is a liar; for the one who does not love his brother whom he has seen, cannot love God whom he has not seen. And this commandment we have from Him, that the one who loves God should love his brother also" (I John 4:20-21).

The only way to properly worship God is to be in fellowship with God and our brothers and sisters. "Behold, how good and how pleasant it is for brothers to dwell together in unity!" (Psalms 133:1). Therefore, our Lord directs us that if we know that a brother has a problem with us, we need first to settle the dispute so that we both can worship God together.

"Therefore I want the men in every place to pray, lifting up holy hands, without wrath and dissension" (I Timothy 2:8).