Upon which. This is supported by the Septuagint and Vulgate. In Deuteronomy 29:25 it is rendered "Because".
caused me to hope. Our hope is based on believing what we have "heard" from God. Compare Hebrews 11:1 with Romans 10:17.
Related Commentaries of Psalms 119:49
Psalms 119:49
49 ZAIN. Remember the word unto thy servant, upon which thou hast caused me to hope.