I have heard it said that the Ten Commandments were Mosaic law (given to Moses in the Old Testament) and we no longer need to follow them since we are now under the New Testament.

I have heard it said we don’t need to follow the laws and precepts of Corinthians because Paul wrote them only to the Church of Corinth.

I have heard people claim promises throughout the Old Testament which were specific only to Israel at a specific time.

Context does matter. Discernment and rightly dividing the word of God requires us to first look at the Holy Bible as a whole. It was written for us. It is directed at the modern day reader. Things written to others in times past are lively and directed at us today.

1 John 2:7 KJV
Brethren, I write no new commandment unto you, but an old commandment which ye had from the beginning. The old commandment is the word which ye have heard from the beginning.

Is not the law that which we have heard from the beginning, whether by faithful preaching or by our own reading of the Bible?

Ecclesiastes 12:13 KJV
Let us hear the conclusion of the whole matter: Fear God, and keep his commandments: for this is the whole duty of man.