Philippians 3:3 NKJV
”For we are the circumcision, who worship God in the Spirit, rejoice in Christ Jesus, and have no confidence in the flesh,”
In Joshua 5:2 the Bible records that "At that time the Lord said unto Joshua, Make thee sharp knives, and circumcise again the children of Israel the second time." Let's be honest, not many of us would've wanted to be Joshua in this situation having to be responsible for the circumcision of an entire nation. If you know anything about circumcision then you know that the demands of such a practice would mean many of them having to go through exposure, vulnerability, and intense pain all for the sake of them remaining in obedience to God and being right with the covenant He established with their fathers.
Many of us today are like that, we are not willing to open up our intimates to allow the surgically precise work of the Holy Spirit upon our hearts to cut off the excesses that have kept us at a stagnant point in our walk with Him. For you that piece of flesh could be anything ranging from ungodly tendencies, lusts or secret desires that are yet to come under the government of God, it could be major character flaws that God knows will jeopardize you in the place of destiny. You already have a good idea what your own piece of flesh is and if you're like Moses (Exodus 4:24-26) who wasn't too willing to get it through with, one day God will come after you, if not for anything other than preserving your destiny and future, I pray you don’t wait that long but that instead you take yourself to that altar having found the courage to muster the words “Lord, go ahead and do it”
Joshua had a very hefty task in front of him and he had to do it with a “sharp knife”, the trouble is that it's hard to predict what your "sharp knife" will be. A difficult situation, an excruciatingly painful experience, suffering the consequences of or discipline for the very misdeeds God is to dealing with, whatever it might be, hold on till that work is done, stay there and don't go anywhere till the work has finished because as stated in Hebrews 12:5-6
“And you have forgotten the exhortation which speaks to you as to sons: “My son, do not despise the chastening of the Lord, Nor be discouraged when you are rebuked by Him; For whom the Lord loves He chastens, And scourges every son whom He receives.”
God only does it to His beloved sons and daughters.