You correctly understand both grace and faith. Both come from God. Having now received these - we are to grow in the grace of God, our knowledge of God and in our faith towards Him. We do this not only by our knowledge of scripture but , primarily by seeking God Himself - to know Him in nature, attributes and character. And, since we, as born again believers, have His divine Spirit now living within us - we can know Him, Love Him and obey Him (in all things) to love others.  We have everything we need to live a holy, spottless and blameless life in this world. If we walk according to the Spirit within us we will not fullfil the deeds (works) of the flesh. But, if we do sin, we have an advocate, Jesus, who is faithful and just to forgive and cleanse us from of all our unrighteousness and sins -  to remain unspotted. We have a choice to obey or not to obey - the commandments of Christ to us - come with both warnings for disobedience and blessings for obedience. If we remain in Him we sin not but, it is also our choice, not to remain. For the believer, their sins no longer condemn them but their fellowship with God is hindered or quenched and so is their growing in grace and faith.  Grace and faith do not eliminate our free-will and they certainly cannot be used as an excuse for our sin and disobedience to Christ's commands. Grace and faith yes, but do not ignore the commands and warnings given to us believers (for good reason) by the Apostles and Christ Jesus Himself - we must put to death the old nature.   Christianity is not something we try our best at but something we do - because we now have God's divine Holy Spirit living within us enabling us to obey all God's requirements.
 
They  (Jews - original branches) were broken off because of unbelief (disobedience), "but YOU (believer) STAND by FAITH." (therefore)  Do not be arrogant, but be afraid. For if God did not spare the natural branches, He will not spare you either.
 
TAKE NOTICE,  THEREFORE, (of who God is) of the kindness and severity of God: severity to those who fell, but kindness to YOU, IF YOU CONTINUE in His kindness. Otherwise YOU ALSO will be CUT OFF.  (Romans 11:20-22)
 
And you (believer) shall be hated of all men for my name's sake: but he that shall ENDURE TIL THE END, THE SAME shall be SAVED. (Mark 13:13)

Because.... you have KEPT MY COMMAND to endure with patience, I will also keep you from the hour of testing (Great Tribulation) that is about to come upon the whole world, to test those who dwell on the earth. (Revelation 3:10)

 The sinners... among My people will be killed in war—all those who say, ‘God will not let any harm come near us.’”  Amos 9:10

IF you call “Father” the one who judges everyone impartially according to what they have done, you must live in reverent fear as long as you are strangers in a strange land. (1 Peter 1:14-17)
 
As obedient children, do not be shaped by the desires that used to influence you when you were ignorant. Instead, BE HOLY in every aspect of your life, just as the one who called you is holy. For it is written, “YOU MUST BE HOLY, because I AM HOLY."

And you shall love the Lord your God with all your heart, and with all your soul, and with all your mind, and with all your strength: this is the first commandment. And the second is like, namely this, You shall love your neighbor as yourself.  (Mark 12:30-31)

IF YOU KEEP My commandments, YOU WILL REMAIN in My love, just as I have kept My Father's commandments and remain in His love. (John 15:10)

Now the end of the commandment is love out of a pure heart, and of a good conscience, and of faith unfeigned: From which some having swerved have turned aside unto vain talk; Desiring to be teachers of the law; understanding neither what they say, nor the things they affirm. (1 Timothy 1:5-7)

Fight the good fight for the FAITH. KEEP HOLDING ON to eternal life, to which YOU WHERE CALLED and about which you gave a good testimony in front of many witnesses. (1 Timothy 6:12)
 
For you have need of ENDURANCE, so that when you have DONE the will of God you may receive what is promised. (Hebrews 10:36)

 "For whoever DOES the will of God is My brother and sister and mother.”  - Jesus

For by Grace through Faith we are saved - BUT... we must OBEY, CONTINUE, REMAIN, KEEP, OVERCOME and ENDURE til the END - as Commanded.  So.. through faith and obedience we may inherit the promises of God.