he bless himself in his heart

For context, in Deuteronomy 29 and 30, the LORD is making His covenant with the Israelites. The LORD has brought them through the Exodus – the forty years of marching, following God’s direction – and they are on the eastern side of the Jordan River. They could have entered the Promised Land almost 40 years earlier, and more directly, if they had not sinned against God and feared the giants of the land. Their fear of the giants was greater than their fear of the LORD. Sadly, it was because, in many ways they were walking by sight, rather than by faith.