A soldier’s heart needs protection from the enemy. Similarly, a Christian’s figurative heart requires shielding from the power of sin.
فَيَصِيرُ مِنَ ٱلْمُسْتَبْعَدِ أَنْ يَرْتَكِبَ مَعْصِيَةً تُخَسِّرُهُ رِضَى ٱللهِ .‏