“For not even those who are circumcised keep the law, but they desire to have you circumcised that they may boast in your flesh”
For not even those who are circumcised keep the law,
The legalistic Judaizers did not keep the law themselves. They knew this was impossible. They were not consistent with their own standards yet they tried to put others under those standards.
“Did not Moses give you the law, yet none of you keeps the law? Why do you seek to kill Me?” (John 7:19).
“For on the one hand there is an annulling of the former commandment because of its weakness and unprofitableness, for the law made nothing perfect; on the other hand, there is the bringing in of a better hope, through which we draw near to God” (Hebrews 7:18-19).
but they desire to have you circumcised that they may boast in your flesh
The word “boast” means to speak loudly, be loud-tongued, vaunt oneself. The legalistic Judaizers were adamant circumcision was essential for salvation and sanctification. They wanted to brag about how many converts they could get.
Religionists are more interested in converts than conversion.
Religionists often profess a religion they themselves cannot perform. They pretend to live with integrity but their lives deny it. Their real motivation is to gain proselytes to their side.