[Neither] height nor depth, nor any other created thing, shall be able to separate us from the love of God which is in Christ Jesus our Lord. Romans 8:39
It is often helpful and interesting to compare how Jesus and Paul approached the same subject in their teachings. Jesus was the plainspoken Shepherd and Teacher who used metaphors and illustrations familiar to His audience. Paul, on the other hand, was a theologian and rabbinic scholar who wrote and spoke in eloquent terms. Comparing their differences provides an expanded understanding of a topic both addressed.
Take eternal security; both taught the same truth but expressed it in different ways. Jesus addressed it when describing Himself as the Good Shepherd (John 10). His sheep would never perish because they are secure in His and the Father’s hand (verses 28-29)—no one could “snatch” them away. Paul, on the other hand, described a long list of more than fifteen circumstances, none of which can separate believers from the love of God in Christ Jesus (Romans 8:35-39). Both Jesus and Paul taught that believers are eternally secure, using different words.
When you go through challenging times, read Jesus’ and Paul’s assuring words. Then rest in the love of God in Christ.
Let us not seek any other ground of assurance than [God’s] own testimony. John Calvin