Because the Holy Spirit only works in this perimeter to help us. And He alone will keep those commandments through you. Remember Jesus says, "Apart from me you can do nothing," John 15:5. The reason Jesus tells us to carry our Cross daily is to receive the benefits the Cross has. Those benefits include; wisdom - knowledge - and understanding, deliverance, healing, sanctification, eternal life, prosperity, joy, a new house, a new car, a husband, a wife, and all the promises in the bible.
What cancels this is when the Believer is living between two Kingdoms. The scripture says, "On purpose, intentionally, God will make sure things do not work out in your life. 1 Corinthians 1:18-31 NASB, James 1:5-8 NASB, James 4:4 NASB
John 14:21 Amplified Bible (AMP)
21 The person who has My commandments and keeps them is the one who [really] loves Me; and whoever [really] loves Me will be loved by My Father, and I will love him and reveal Myself to him [I will make Myself real to him].”