God’s Word is “sufficiently perspicuous [clear] to be understood by the people, in the use of ordinary means and by the aid of the Holy Spirit in all things necessary to faith or practice, without the need of any infallible interpreter.” 1 (clarification mine)
The clarity of Scripture has also been referred to as the “perspicuity” of Scripture. The truth here is not that Scripture is always easy to understand, but that, as the the Westminster Confession of Faith (1.7) explains: “All things in Scripture are not alike plain in themselves, nor alike clear unto all. Yet, those things that are necessary to be known, believed, and observed for salvation are so clearly propounded, and opened in some place of Scripture or another, that not only the learned, but the unlearned, in a due use of the ordinary means, may attain unto a sufficient understanding of them.”
John 16:13 emphasizes the instrumental nature of the Spirit in our understanding of Scripture: “when the Spirit of truth comes, he will guide you into all the truth, for he will not speak on his own authority, but whatever he hears he will speak, and he will declare to you the things that are to come.”
God has given His children His Word and the ability to sufficiently understand His Word through His Spirit. One of the wonders of the way God designed this is that those who seek Him diligently through it increasingly enjoy the unfathomable riches of it (Ephesians 3:8, 2 Timothy 3:16-17).