In a synthetic relationship one idea leads to another or is derived from the prior. It can be cause and effect, an explanation, or a condition followed by a consequence.
The LORD is my shepherd; → I shall not want.
The fact that the Lord God is watching over me like a shepherd leads to the realization that my needs will be taken care of.
Let them praise Your great and awesome name → -- He is holy.
The last phrase explains why people should praise God’s name.
If one wished to contend with Him, → He could not answer Him one time out of a thousand.
The reason men cannot argue with God is that we cannot answer His points.
Lift up your heads, O you gates! Lift up, you everlasting doors! → And the King of glory shall come in.
Styles can be combined. Here two synonymous phrases command an opening to be made and the last phrase explains why it is necessary.