Proverbs 4:23 Above all else, guard your heart, for it is the wellspring of life.
What does it mean for me to guard my heart? The word guard is the word Nasar meaning "to guard, protect, keep, obey; to observe, behold, watch, inspect. Used to denote guarding a vinyard..., a fig tree..., and a fortress. Those who performed this function were called watchmen...In an ethical sense one can guard his mouth (Ps 141:3; Pr 13:3), his path in life (Pr 16:17), his heart (Pr 4:23), His lips (Ps 141:3), and his tongue (Ps 34:13)...Israel was likened to a vineyard and the Lord served as her keeper (Job 7:20). (Key Word Study Lexical Aids)
I would say part of guarding your heart means confession of your sins, examination of your heart, and a careful inspection of what you let in and out of your heart and mind. What you watch, where you go, who your friends are, what you listen to, what you set your affections on, and choosing obedience not based on feeling but on truth. Weeding out roots of bitterness, unforgiveness, disobedience, lust, immorality, gossip, and so many other things that seek to ensnare your heart. Knowing the truth is what will set us free from the deceitfulness of our own hearts.
Heart is the word leb here meaning "the center, the middle of something... Leb however, is more commonly used for the center of man's inner or immaterial nature...In the bible the whole spectrum of human emotions is attributed to the heart...Leb is used to signify the mind (2 Ch 9:23), good sense (Pr 10:8), and discernment (2 Ki 5:26). Wisdom and understanding reside in the heart (1 Ki 3:12, Pr 16:23). The heart can be deceived (Isa 44:20) and is the point of origin of moral evil (Jer 17:9). It is the seat of the will (Nu 16:28; Jdg 9:3; 2 Ch 12:14). To refuse to make the proper decision is to harden the heart..." (Key Word Study Lexical Aids)
So we are to guard the core of our being...the center of our emotions and our inner or immaterial nature. We do this by paying attention to His instruction (vs 20-22) that is what will keep our hearts with all diligence...the attention and application to Gods word.
Here is what The Bible Knowledge Commentary says: " The heart should be guarded for out of it (a wellspring) come one's actions (cf. Luke 6:45). Here the word "heart" means more than mental capacity; it also encompasses one's values (cf Matt. 6:21)."
These verses apply the command to guard one's heart (v. 23), including what one says (v. 24), sees (v. 25), and does (vv. 26-27).
Lord, please give me wisdom to know what's right for my heart and the courage to do it. Please stand at the door of my heart with the truth of Your Word and guard it for me when i am incapable. You know my innermost thoughts and desires, the "feelings" I describe often. Please help me to focus on Your truths and not my feelings, today and every day.