God said to Abraham, This is the covenant with me which you are to keep between me and you, and your seed after you: every male among you is to be circumcised; and you are to circumcise the flesh of your foreskin, to be a sign of the covenant between me and you. Gen. 17:9-11.

This covenant, or its sign, was later confirmed by Moses (Lev. 12:1-3). Because this church was distinguished from others by that sign, the Children of Israel were ordered to be circumcised again before crossing the Jordan (Joshua, chapter 5). The reason was that the land of Canaan represented the church, and the river Jordan being brought into it. In addition, so that they should remember that sign when actually in the land of Canaan, they received this order:

When you come into the land and plant any kind of tree for food, you are to regard its fruit as uncircumcised*; for three years it is to be uncircumcised for you, it is not to be eaten. Lev. 19:23.

[2] Circumcision represented and so stood for the rejection of the lusts of the flesh, and thus purification from evils, in much the same way as baptism. This is established from the passages in the Word where it is said that they should circumcise their hearts, as the following:

Moses said, Circumcise the foreskin of your heart, and do not be stiffnecked. Deut. 10:16.

Jehovah God will circumcise your heart and your seed's heart, so that you will love Jehovah your God with all your heart, and with all your soul, so that you may live. Deut. 30:6.

In Jeremiah:

Circumcise yourselves for Jehovah, so that He may take away the foreskins of your hearts, the man of Judah and the inhabitants of Jerusalem, so that my wrath may not go forth like fire on account of the wickedness of your deeds. Jer. 4:4.

In Paul:

In Jesus Christ neither is circumcision of any value, nor is uncircumcision, but faith working through charity, and a new creation. Gal. 5:6; 6:15.

These passages now make it plain that baptism was instituted to take the place of circumcision, because the circumcision of the heart was represented by the circumcision of the flesh; and this too meant purification from evils, for evils of every kind arise from the flesh, and the foreskin means its filthy loves. It is because circumcision and baptismal washing have a similar meaning that it is said in Jeremiah:

Circumcise yourselves for Jehovah, so that He may take away the foreskins of your hearts. Jer. 4:4.

and shortly afterwards:

Wash your heart free from wickedness, Jerusalem, so that you may be saved. Jer. 4:14.

The Lord teaches in Matthew (15:18, 19) what circumcision and the washing of the heart means.

* i.e. forbidden.