In the Old Testament the idea of ascending was linked to two activities. First, it described drawing near to the presence of God. The Tabernacle was set on a hill and people went up to it. Later, the Temple was built on a mountain in Jerusalem and there is a section in the Book of Psalms, called the Psalms of Ascent (120-134), which describe the worshippers’ approach to the Temple at the festival periods of Israel. So Jesus, when He ascended, entered God’s presence.
R.C. Sproul