<<something unknown or not understood>>

The ‘mystery of His will’ was the plan of salvation (hidden until Jesus rose again, victorious over death) whereby all who choose to become His children receive the Holy Spirit as a deposit of what is to come when all believers will be with Him forever in heaven (1 Cor 2:6-10, 15:51; Eph 1:9-14; Col 1:26,27). As Satan has blinded the spiritual eyes of people so they are unaware or ignore the offer of salvation, we

It should be clear to others we are a Jesus follower

should pray that as believers we may fearlessly make known the mystery of the gospel and be sensitive to the Holy Spirit as we live for Christ and interact with the unsaved (2 Cor 4:4; Eph 6:19).

Because we do not possess the attributes of God, some things will to remain beyond our level of understanding, yet we are to live by what has been
clearly revealed, and trust Him for the rest (Deut 29:29). Other things will be revealed to us at the end of time (Isa 40:5)

While we do not know why many things happen to us, it is our responsibility to love God and praise Him at all times and in all situations, including the bewildering times of confusion which call for a sacrifice of praise (Ps 34:1; Eph 5:20; 1 Thes 5:18). He desires the long-term best for us, and wants to develop His character in us (which only comes about as we yield to Him in the situations of life), while we would rather settle for comfort and the end result, not the process by which it comes. When things don’t make sense keep walking with Him in faith and entrust yourself to His loving arms. He
doesn’t give us anything unbeneficial or harmful – even if we may question it at the time because we do not comprehend His loving intentions for us
as, in His wisdom and sovereignty, He operates in a different way to us (Deut 33:27; Isa 55:8,9; Mt 7:7-11).  Satan must gain permission to harass those believers walking with God as His eye is always on His children (Job 1:8-12, 2:3-6; Ps 31:5,15; Lk 22:31,32).  

See also: questions, secret, why.