Am I My Brother's Keeper?

The major text employed in this teachings is:
Genesis 4:8-16,24
And Cain talked with Abel his brother: and it came to pass, when they were in the field, that Cain rose up against Abel his brother, and slew him. And the Lord said unto Cain, Where is Abel thy brother? And he said, I know not: Am I my brother's keeper? And he said, What hast thou done? the voice of thy brother's blood crieth unto me from the ground. And now art thou cursed from the earth, which hath opened her mouth to receive thy brother's blood from thy hand; When thou tillest the ground, it shall not henceforth yield unto thee her strength; a fugitive and a vagabond shalt thou be in the earth. And cain said unto the Lord, My punishment is greater than I can bear. Behold, thou has driven me out this day from the face of the earth; and from thy face shall i be hid; and I shall be a fugitive and a vagabond in the earth; and it shall come to pass, that every one that findeth me shall slay me. And the Lord said unto him, Therefore whosoever slayeth Cain, vengeance shall be taken on him sevenfold. And the Lord set a mark upon Cain, lest any finding him should kill him. And cain went out from the presence of the Lord, and dwelt in the land of Nod, on the east of Eden. If Cain shall be avenged sevenfold, truly lamech seventy and sevenfold.
New Testament related texts are:

Galatians 6:1,2 Brethren, if a man be overtaken in a fault, ye which are spiritual, restore such a one in the spirit of meekness; considering thyself, lest thou also be tempted. Bear ye one another's burdens, and so fulfill the law of Christ.

Romans 12:15 Rejoice with them that do rejoice, and weep with them that weep.

1 Corinthians 12:12,22,25,26 For as the body is one, and hath many members, and all the members of that one body, being many, are one body: so also is Christ. Nay, much more those members of the body, which seem to be more feeble are necessary: That there should be no schism in the body; but that the members should have the same care one for another. And whether one member suffer, all the members suffer with it; or one member be honoured, all the members rejoice with it.
1 John 4:20, 21 If a man say, I love God, and hateth his brother, he is a liar: for he that loveth not his brother whom he hath seen, how can he love God whom he hath not seen? And this commandment have we from him, That he who loveth God loveth his brother also.

God, in his infinite wisdom, has placed all the members of the church in one body. He has provided for the safety of each individual member. He has no other plan: He has no other purpose. This expression, on the local church level, demands a commitment, a loyalty, an involvement, a faithfulness.