Concerning the Spirits direction of the heart
The Bible says: he who obeys what has been commanded by Paul, the LORD will direct our hearts (2Th3:1-5). Why? The LORD is Spirit (2Co3:17). What Paul speaks is the word of GOD (Ac13:44-45), and the word of GOD is Spirit (Eph6:17). To lay the word of GOD is to lay His Spirit to heart. If we cast His words behind, we have actually become an evil person before Him (Ps50:16-17). Of course, there is no direction in the heart from the LORD. The words of the Bible were the LORD (2Ch34:21, 2Ki22:13).
Those who are led by the Spirit of GOD are children of GOD (Rom8:14); the law is spiritual (Rom7:14). Then we have to ask ourselves whether the law has been written in our hearts (Heb8:10-12). If the law is written within, a new and living way is opened for us, through the curtain of the temple, that is, the body of Jesus (Heb10:16-20). No doubt that the Spirit will lead us as we acknowledge him in everything, not leaning on our own understanding (Pr3:5).
And if the LORD guides us, we will be like a watered garden, like a spring of water whose waters never fail (Isa58:11), that is, streams of living water will flow out of our belly (Jn7:37-38). The water is the water of life given by Jesus (Jn4:14), and the word (Eph5:26).
To be directed by the LORD, we need to be warned against going our own ways, serving our own interests and speaking our own words (Isa58:13) so that the LORD will feed us with the heritage of Jacob (14). The heritage is the LORD (Eze44:28).